amphotericin-b and Disease-Models--Animal

The biological properties of elastase and Aspergillus flavus elastase inhibitor (AFLEI) from A. flavus were examined. Pathogenicity of elastase was investigated in mice immunocompromised with cyclophosphamide, cyclosporine, prednisolone and carrageenan. Compared to cyclophosphamide immunocompromised mice treated with the spores of elastase nonproducing strain, cyclophosphamide immunocompromised mice treated with the spores of elastase producing strain had a significantly shorter survival rate. Molecular mass of AFLEI was determined to be 7525.8 Da. The elastolytic activity of elastases from A. flavus, and human leukocytes were inhibited by AFLEI. The primary structure of AFLEI was determined by the Edman sequencing procedure. The search for amino acid homology with other proteins demonstrated that amino acid residues 1 to 68 of AFLEI are 100% identical to residues 20 to 87 of the hypothetical protein AFUA_3G14940 of A. fumigatus. When immunocompromised mice administered of cyclophosphamide were infected by inhalation of A. flavus then administered amphotericin B (AMPH) alone or in combination with AFLEI, survival rate tended to be higher with combination treatment than with AMPH alone. Moreover, although extensive bleeding was seen in pathology sections taken from rat lung resected 24 h after elastase was administered to the lung via the bronchus, this bleeding was inhibited by AFLEI. The X-ray analysis has revealed that the structure of this inhibitor was wedge shaped and composed of a binding loop and a scaffold protein core. As synthetic-inhibitor strongly inhibited cytotoxicity induced by elastase in human-derived cells, it could prove beneficial for the treatment of pulmonary aspergillosis.

Topics: Amphotericin B; Animals; Aspergillus flavus; Disease Models, Animal; Enzyme Inhibitors; Hemorrhage; Humans; Immunocompromised Host; Lung Diseases; Mice; Pancreatic Elastase; Pulmonary Aspergillosis; Rats

Mucormycosis mostly affects immunocompromised patients and is associated with a high morbidity and mortality despite currently available treatments. In that context, combination therapy might be the key to a better outcome for these patients. Purpose of this review is to summarise and to discuss the current combination data obtained in vitro, in vivo in animal models of mucormycosis, and in patients. In vitro combination studies showed that most of the interactions between antifungal drugs were indifferent, even though that some synergistic interactions were achieved for the combination of echinocandins with either azoles or amphotericin B. Importantly, antagonism was never observed. Animal models of mucormycosis focused on infections caused by Rhizopus arrhizus, neglecting most other species responsible for human disease. In these experimental animal models, no strong interactions have been demonstrated, although a certain degree of synergism has been reported in some instances. Combinations of antifungals with non-antifungal drugs have also been largely explored in vitro and in animal models and yielded interesting results. In patients with ketoacidosis and rhino-orbito-cerebral infection, combination of polyene with caspofungin was effective. In contrast, despite promising experimental data, adjunctive therapy with the iron chelator deferasirox was unfavourable and was associated with a higher mortality than monotherapy with liposomal amphotericin B. More combinations have to be tested in vitro and a much larger panel of Mucorales species has to be tested in vivo to give a valuable statement if antifungal combination therapy could be an effective treatment strategy in patients with mucormycosis.

Topics: Amphotericin B; Animals; Antifungal Agents; Azoles; Disease Models, Animal; Drug Synergism; Drug Therapy, Combination; Humans; Immunocompromised Host; Lipopeptides; Mice; Microbial Sensitivity Tests; Mucorales; Mucormycosis

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus; Clinical Trials as Topic; Disease Models, Animal; Drug Interactions; Drug Therapy, Combination; Echinocandins; Humans; Immunosuppression Therapy; Survival Rate; Triazoles

Combination therapy with amphotericin B and flucytosine is considered to be the treatment of choice for cryptococcal infections. However, for other infections and combinations of antifungal infections, the data are less clear-cut. The concurrent use of amphotericin B with an azole has elicited controversy, given the potential of antimicrobial antagonism. The results of one recent candidemia study suggest that the potential antagonism may not be an issue; the combination of amphotericin B and fluconazole provided more effective clearance of Candida from the bloodstream than did fluconazole used alone. Several in vitro and animal studies have shown antagonism between the azoles and amphotericin B for aspergillosis. However, introduction of the new class of agents that target beta-glucan synthase (echinocandins) has invigorated the prospects of combination therapy. The echinocandins and polyenes are not antagonistic, and there is evidence that the echinocandins may provide additive to synergistic activity in combination with triazoles. For patients whose aspergillosis is progressing despite monotherapy, the addition of a second agent, such as an echinocandin, may be reasonable.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Azoles; Candidiasis; Caspofungin; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Administration Schedule; Drug Therapy, Combination; Echinocandins; Fluconazole; Humans; In Vitro Techniques; Lipopeptides; Lipoproteins; Micafungin; Mycoses; Peptides, Cyclic; Pyrimidines; Randomized Controlled Trials as Topic; Time Factors; Treatment Outcome; Triazoles; Voriconazole

In recent years, the frequency of infections caused by Aspergillus sp. has been on the rise. Immunocompromised patients are especially vulnerable to such infections. The polyene antibiotic amphotericin B is currently considered to be therapeutically the most effective drug against Aspergillus-induced infections. In the present review, the clinical efficacy of amphotericin B, its toxicities and various routes of applications, are discussed. Different combinations of amphotericin B with other drugs have also been reviewed, along with the anti-Aspergillus activity of various other antibiotics and some ester derivatives of amphotericin B.

Topics: Amphotericin B; Animals; Anti-Bacterial Agents; Aspergillosis; Aspergillosis, Allergic Bronchopulmonary; Disease Models, Animal; Drug Therapy, Combination; Humans; Immunocompromised Host; Lung Diseases, Fungal

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Amphotericin B; Animals; Aspergillosis; Aspergillus fumigatus; Child; Disease Models, Animal; Endophthalmitis; Eye Infections, Fungal; Female; Humans; Infant; Male; Middle Aged; Rabbits

Topics: Acidosis, Renal Tubular; Aldosterone; Amiloride; Amphotericin B; Animals; Carbon Dioxide; Disease Models, Animal; Hydrogen; Hydrogen-Ion Concentration; Kidney Tubules, Distal; Lithium; Partial Pressure; Ureteral Obstruction

Topics: Acidosis, Renal Tubular; Amiloride; Amphibians; Amphotericin B; Animals; Biological Transport, Active; Carbonates; Disease Models, Animal; Humans; Hydrogen-Ion Concentration; In Vitro Techniques; Kidney Tubules; Kidney Tubules, Distal; Lithium; Membrane Potentials; Rats; Turtles

Topics: Amphotericin B; Animals; Antifungal Agents; Antitubercular Agents; Crystallization; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Hypersensitivity; Drug Interactions; Glomerular Filtration Rate; Humans; Kidney; Kidney Diseases; Solubility; Sulfonamides

Amphotericin B is widely used for the treatment of Macrorhabdus ornithogaster infections. To date, however, there have been no randomized controlled trials confirming its efficacy where cure was confirmed by postmortem examination. To determine the efficacy of amphotericin B against M. ornithogaster, a three-part study was undertaken. Treatment outcomes of M. ornithogaster infected birds treated amphotericin B were reviewed. A pilot treatment trial with two naturally infected birds (Melopsittacus undulatus and Agapornis roseicollis) was undertaken, administering amphotericin B at 100 mg/kg twice daily for 30 days. Finally, a randomized controlled trial using experimentally infected chickens treated with amphotericin B at 25 mg/kg and 100 mg/kg twice daily for 10 days was performed. Retrospective analysis indicated treatment failure in 80.4% of 36 cases that met the inclusion criteria. The pilot study showed that amphotericin B did not clear, but significantly decreased Macrorhabdus ornithogaster burden, followed by profound rebound effect of the number of organisms shed in the feces. Finally, the randomized controlled trial found that amphotericin B given at 100 mg/kg did not clear, but significantly decreased the burden of M. ornithogaster compared with both the 25 mg/kg group (P = .037) and the no treatment control group (P = .001). A strong curvilinear correlation between body weight and M. ornithogaster infection burden was present in the infected chickens. These findings represent treatment failure in three scenarios and indicate that treatment with amphotericin B has poor efficacy against Macrorhabdus ornithogaster.

Topics: Amphotericin B; Animals; Antifungal Agents; Australia; Bird Diseases; Birds; Chickens; Colony Count, Microbial; Disease Models, Animal; Drug Resistance, Fungal; Female; Male; Mycoses; Random Allocation; Saccharomycetales; Treatment Outcome

Eumycetoma is a subcutaneous implantation mycosis often found in the foot. One of the hallmarks of eumycetoma is the formation of grains. These grains are either black or white, and the consistency and morphology differs per causative agent. The two most common causative agents of black-grain eumycetoma are Madurella mycetomatis and Falciformispora senegalensis. Since grains cannot be formed in vitro, in vivo models are needed to study grain formation. Here, we used the invertebrate Galleria mellonella to establish an in vivo grain model for F. senegalensis. Three different F. senegalensis strains were selected, and four different inocula were used to infect G. mellonella larvae, ranging from 0.04 mg/larvae to 10 mg/larvae. Larval survival was monitored for 10 days. Grain formation was studied macroscopically and histologically. The efficacy of antifungal therapy was determined for itraconazole, amphotericin B, and terbinafine. A concentration of 10 mg F. senegalensis per larva was lethal for the majority of the larvae within 10 days. At this inoculum, grains were formed within 24 h after infection. The grains produced in the larvae resembled those formed in human patients. Amphotericin B given at 1 mg/kg 4 h, 28 h, and 52 h after infection prolonged larval survival. No enhanced survival was noted for itraconazole or terbinafine. In conclusion, we developed a F. senegalensis grain model in G. mellonella larvae in which grains were formed that were similar to those formed in patients. This model can be used to monitor grain formation over time and study antifungal efficacy.. Within eumycetoma lesions, the causative agents are embedded in grains. However, the grains differ per causative agent. In this study, we developed a grain model of Falciformispora senegalensis in the larvae of Galleria mellonella. This model can be used in the future to study the efficacy of novel antifungal agents.

Topics: Amphotericin B; Animals; Antifungal Agents; Disease Models, Animal; Humans; Itraconazole; Larva; Moths; Mycetoma; Terbinafine

Treatment of visceral leishmaniasis (VL) is compromised by drug toxicity, high cost and/or the emergence of resistant strains. Though canine vaccines are available, there are no licensed prophylactic human vaccines. One strategy to improve clinical outcome for infected patients is immunotherapy, which associates a chemotherapy that acts directly to reduce parasitism and the administration of an immunogen-adjuvant that activates the host protective Th1-type immune response. In this study, we evaluated an immunotherapy protocol in a murine model by combining recombinant (r)LiHyp1 (a hypothetical amastigote-specific Leishmania protein protective against Leishmania infantum infection), with monophosphoryl-lipid A (MPLA) as adjuvant and amphotericin B (AmpB) as reference antileishmanial drug. We used this protocol to treat L. infantum infected-BALB/c mice, and parasitological, immunological and toxicological evaluations were performed at 1 and 30 days after treatment. Results showed that mice treated with rLiHyp1/MPLA/AmpB presented the lowest parasite burden in all organs evaluated, when both a limiting dilution technique and qPCR were used. In addition, these animals produced higher levels of IFN-γ and IL-12 cytokines and IgG2a isotype antibody, which were associated with lower production of IL-4 and IL-10 and IgG1 isotype. Furthermore, low levels of renal and hepatic damage markers were found in animals treated with rLiHyp1/MPLA/AmpB possibly reflecting the lower parasite load, as compared to the other groups. We conclude that the rLiHyp1/MPLA/AmpB combination could be considered in future studies as an immunotherapy protocol to treat against VL.

Topics: Adjuvants, Immunologic; Amebicides; Amphotericin B; Animals; Clinical Protocols; Disease Models, Animal; Drug Therapy, Combination; Female; Immunotherapy; Leishmaniasis, Visceral; Lipid A; Mice; Mice, Inbred BALB C; Protozoan Proteins; Recombinant Proteins

Prophylactic antifungal therapy is widely adopted clinically for critical patients and effective in reducing the morbidity of invasive fungal infection and improves outcomes of those diagnosed patients; however, it is not associated with higher overall survival. As intestinal commensal fungi play a fundamental role in the host immune response in health and disease, we propose that antifungal therapy may eliminate intestinal fungi and aggravate another critical syndrome, sepsis. Here, with murine sepsis model, we found that antifungal therapy with fluconazole dismissed intestinal fungal burden and aggravated endotoxin-induced but no gram-positive bacteria-induced sepsis. Nevertheless, antifungal therapy did not exert its detrimental effect on germ-free mice. Moreover, colonizing more commensal fungi in the mouse intestine or administration of fungal cell wall component mannan protected the mice from endotoxin-induced sepsis. On the molecular level, we demonstrated that antifungal therapy aggravated endotoxin sepsis through promoting Gasdermin D cleavage in the distal small intestine. Intestinal colonization with commensal fungi inhibited Gasdermin D cleavage in response to lipopolysaccharide challenge. These findings show that intestinal fungi inhibit Gasdermin D-mediated pyroptosis and protect the mice from endotoxin-induced sepsis. This study demonstrates the protective role of intestinal fungi in the pathogenesis of endotoxin-induced sepsis in the laboratory. It will undoubtedly prompt us to study the relationship between antifungal therapy and sepsis in critical patients who are susceptible to endotoxin-induced sepsis in the future.

Topics: Amphotericin B; Animals; Antifungal Agents; Disease Models, Animal; Dysbiosis; Feces; Fluconazole; Fungi; Gastrointestinal Microbiome; Lipopolysaccharides; Mannans; Methicillin-Resistant Staphylococcus aureus; Mice, Inbred C57BL; Mice, Knockout; Phosphate-Binding Proteins; Pore Forming Cytotoxic Proteins; Sepsis; Staphylococcal Infections

Treatment options for Exserohilum rostratum meningoencephalitis and other causes of phaeohyphomycosis of the central nervous system (CNS) are limited, while mortality and morbidity remain high. We therefore evaluated isavuconazole, a new antifungal triazole in comparison to liposomal amphotericin B (LAMB), in vitro and in the rabbit model of Exserohilum rostratum meningoencephalitis. We hypothesized that isavuconazole alone or in combination with LAMB or micafungin may be alternative options for treatment of CNS phaeohyphomycosis. We therefore investigated the in vitro antifungal activity of isavuconazole alone or in combination with amphotericin B deoxycholate (DAMB) or micafungin and efficacy of treatment with isavuconazole and LAMB in a rabbit model of experimental E. rostratum meningoencephalitis. Combination checkerboard plates were used to determine the minimum inhibitory concentrations, minimal lethal concentrations, fractional inhibitory concentration indices, and Bliss surface analysis of isavuconazole and amphotericin B deoxycholate (DAMB), either alone or in combination. As there were no in vitro synergistic or antagonistic interactions for either combination of antifungal agents against the E. rostratum isolates, in vivo studies were conducted with isavuconazole and LAMB as monotherapies. Rabbits were divided in following groups: treated with isavuconazole at 60 mg/kg/d (ISAV60), LAMB at 5.0 (LAMB5), 7.5 (LAMB7.5), and 10 mg/kg/d (LAMB10), and untreated controls (UC). In ISAV60-, LAMB5-, LAMB7.5-, and LAMB10-treated rabbits, significant reductions of fungal burden of E. rostratum in cerebral, cerebellar, and spinal cord tissues (P < 0.01) were demonstrated in comparison to those of UC. These antifungal effects correlated with significant reduction of CSF (1→3)-β-D-glucan levels vs UC (P < 0.05). These data establish new translational insights into treatment of CNS phaeohyphomycosis.

Topics: Amphotericin B; Animals; Antifungal Agents; Ascomycota; Central Nervous System Diseases; Disease Management; Disease Models, Animal; Drug Therapy, Combination; Female; Humans; Microbial Sensitivity Tests; Nitriles; Phaeohyphomycosis; Pyridines; Rabbits; Triazoles

Present treatment regimen on visceral leishmaniasis has multiple limitations including severe side effects, toxicity, and resistance of Leishmania strains. Amphotericin B is a well-established pharmacologically approved drug; however, mainly toxicity is a foremost issue with that drug. Recently, our group identified eugenol oleate as an anti-leishmanial immunomodulatory compound. The important objectives of this present study was to evaluate the possible synergistic effect of eugenol oleate with amphotericin B to reduce the toxicity of this approved drug. Results obtained from this study signified that combination of eugenol oleate and amphotericin B showed indifferent combinatorial effect against promastigotes with xΣFIC 1.015, while, moderate synergistic activity with xΣFIC 0.456 against amastigotes. It was also notable that eugenol oleate (2.5 μM) with low concentrations of amphotericin B (0.3125 μM) showed 96.45% parasite reduction within L. donovani-infected murine macrophages. Furthermore, eugenol oleate and amphotericin B significantly (p < 0.01) enhanced the nitrite generation, and pro-inflammatory cytokines (IL-12, IFN-γ and TNF-α) in infected macrophages in vitro and in BALB/c mice in vivo. Eugenol oleate (10 mg/Kg b. wt.) with amphotericin B (1 mg/Kg b.wt.) significantly (p < 0.01) controlled the parasite burden in liver by 96.2% and in spleen by 93.12%. Hence, this study strongly suggested the synergic potential of eugenol oleate with low concentration of amphotericin B in experimental visceral leishmaniasis through anti-leishmanial immune response.

Topics: Amphotericin B; Animals; Cells, Cultured; Cytokines; Disease Models, Animal; Drug Synergism; Drug Therapy, Combination; Female; Host-Parasite Interactions; Inflammation Mediators; Leishmania donovani; Leishmaniasis, Visceral; Liver; Macrophages, Peritoneal; Mice, Inbred BALB C; Nitrites; Parasite Load; Spleen; Th1 Cells; Th1-Th2 Balance; Th2 Cells; Trypanocidal Agents

Amphotericin B-deoxycholate (Fungizone [FZ]) is a widely used potent antimycotic drug in spite of its nephrotoxic effect via different mechanisms. The effect of FZ on renal cell bioenergetics is not clear. The current study evaluated the effect of FZ on the bioenergetics of albino rats' isolated renal proximal tubule cells (PTCs). The cytotoxic effect of FZ on the isolated renal cells was assessed by MTT and lactate dehydrogenase (LDH) assays. The effect of FZ on the PTCs uptake (OAT1 and OCT2) and efflux (P-gp and MRP2) transporters was evaluated. Then, the effect of FZ on mitochondria was assessed by studying complexes I-IV activities, lactate assay, oxygen consumption rates (OCR), and western blotting for all mitochondrial complexes. Moreover, the effect of FZ on mitochondrial membrane fluidity (MMF) and fatty acids composition was evaluated. Additionally, the protective effect of coenzyme q10 was studied. Outcomes showed that FZ was cytotoxic to the PTCs in a concentration and time-dependent patterns. FZ significantly inhibited the studied uptake and efflux tubular transporters with inhibition of the mitochondrial complexes activities and parallel increase in lactate production and decrease in OCRs. Finally, FZ significantly reduced the expression of all mitochondrial complexes in addition to significant increase in MMF and MMFA concentration. Coenzyme Q10 was found to significantly decrease FZ-induced cytotoxicity and transporters impairment in the PTC. FZ significantly inhibits bioenergetics of PTC, which may stimulate the cascade of cell death and clinical nephrotoxicity.

Topics: Amphotericin B; Animals; Antifungal Agents; Cells, Cultured; Deoxycholic Acid; Disease Models, Animal; Drug Combinations; Humans; Kidney Tubules, Proximal; Mitochondria; Mycoses; Rats; Rats, Wistar

Amphotericin B (AmB) is used to treat cryptococcal meningoencephalitis. However, the mortality rate remains high. Higher doses of AmB in deoxycholate buffer (AmBd) are toxic to human red blood cells (hRBC) and have no effect on brain organism load in mice. Here we show that while AmBd lysed 96% of hRBC, AmB complexed with gold nanoparticles (AuNP-SA-AmB) lysed only 27% of hRBC. In vitro growth of C. neoformans was inhibited by 0.25 μg/ml AmBd and 0.04 μg/ml of AuNP-SA-AmB. In mice infected with C. neoformans, five daily treatments with AuNP-SA-AmB containing 0.25 mg/kg AmB significantly lowered the fungal burden in the brain tissue compared to either untreated or treatment with 0.25 mg/kg of AmBd. When a single dose of AmBd was injected intravenously into BALB/c mice, 81.61% of AmB cleared in the α-phase and 18.39% cleared in the β-phase at a rate of 0.34% per hour. In contrast, when AuNP-SA-AmB was injected, 49.19% of AmB cleared in the α-phase and 50.81% of AmB cleared in the β-phase at a rate of 0.27% per hour. These results suggest that AmB complexed with gold nanoparticles is less toxic to hRBC, is more effective against C. neoformans and persists longer in blood when injected into mice resulting in more effective clearing of C. neoformans from the brain tissue.. Amphotericin B (AmB) was complexed with gold nanoparticles (AuNP-SA-AmB) to improve brain delivery. AuNP-SA-AmB was more effective than AmB alone in clearing of Cryptococcus neoformans from the brain tissue of infected mice. This may be due to longer plasma half-life of AmB as AuNP-SA-AmB.

Topics: Amphotericin B; Animals; Antifungal Agents; Brain Diseases; Cryptococcosis; Cryptococcus neoformans; Disease Models, Animal; Erythrocytes; Gold; Humans; Mice; Rodent Diseases

Leishmaniasis occurs in the five continents and represents a serious public health challenge, but is still a neglected disease, and the current pharmacological weaponry is far from satisfactory. Triglyceride-rich nanoparticles mimicking chylomicrons (TGNP) behave metabolically like native chylomicrons when injected into the bloodstream. Previously we have shown that TGNP as vehicle to amphothericin B (AB) for treatment of fungi infection showed reduced renal toxicity and lower animal death rates compared to conventional AB. The aim of the current study was to test the tolerability and effectiveness of the TGNP-AB preparation in a murine model of Leishmania amazonensis infection. The in vitro assays determined the cytotoxicity of TGNP-AB, AB, and TGNP in macrophages and promastigote forms and the leishmanicidal activity in infected macrophages. The in vivo toxicity tests were performed in healthy mice with increasing doses of TGPN-AB and AB. Then, animals were treated with 2.5 mg/kg/day of AB, 17.5 mg/kg/day of TGNP-AB, or TGNP three times a week for 4 weeks. TGNP-AB formulation was less cytotoxic for macrophages than AB. TGNP-AB was more effective than AB against the promastigotes forms of the parasite and more effective in reducing the number of infected macrophages and the number of amastigotes forms per cell. TGNP-AB-treated animals showed lower hepatotoxicity. In addition, TGNP-AB group showed a marked reduction in lesion size on the paws and parasitic load. The TGNP-AB preparation attained excellent leishmanicidal activity with remarkable lower drug toxicity at very high doses that, due to the toxicity-buffering properties of the nanocarrier, become fully tolerable.

Topics: Amphotericin B; Animals; Antiprotozoal Agents; Cell Line; Chylomicrons; Disease Models, Animal; Drug Compounding; Female; Leishmaniasis, Cutaneous; Macrophages; Mice; Mice, Inbred BALB C; Molecular Mimicry; Nanoparticles; Parasite Load; Triglycerides

Topics: Administration, Cutaneous; Amphotericin B; Animals; Antiprotozoal Agents; Disease Models, Animal; Drug Combinations; Drug Compounding; Elasticity; Female; Humans; Inhibitory Concentration 50; Leishmania; Leishmaniasis, Cutaneous; Liposomes; Mice; Nanoparticles; Parasite Load; Particle Size; Permeability; Phosphorylcholine; Skin

Cryptococcosis is a common opportunistic infection in patients with advanced HIV infection and may also affect immunocompetent patients. The available antifungal agents are few and other options are needed for the cryptococcosis treatment. In this work, we first analyzed the virulence of twelve C. neoformans and C. gattii strains assessing capsule thickness, biofilms formation, and survival and morbidity in the invertebrate model of Galleria mellonella and then we evaluated the antifungal activity of voriconazole (VRC) in vitro and in vivo also using G. mellonella. Our results showed that all Cryptococcus spp. isolates were able to produce capsule and biofilms, and were virulent using G. mellonella model. The VRC has inhibitory activity on planktonic cells with MIC values ranging from 0.03 to 0.25 μg/mL on Cryptococcus spp.; and these isolates were more tolerant to fluconazole (ranging from 0.25 to 16 μg/mL), the triazol agent often recommended alone or in combination with amphotericin B in the cryptococcosis therapy. In contrast, mature biofilms were less susceptible to the VRC treatment. The VRC (10 or 20 mg/kg) treatment of infected G. mellonella larvae significantly increased the larval survival when compared to the untreated group for the both Cryptococcus species and significantly decreased the fungal burden and dissemination in the larval tissue. Our findings corroborate with the literature data, supporting the potential use of VRC as an alternative for cryptococcosis treatment. Here, we emphasize the use of G. mellonella larval model as an alternative animal model for studies of antifungal efficacy on mycosis, including cryptococcosis.

Topics: Amphotericin B; Animals; Antifungal Agents; Biofilms; Cryptococcosis; Cryptococcus gattii; Disease Models, Animal; Fluconazole; Humans; Larva; Microbial Sensitivity Tests; Moths; Voriconazole

Cryptococcosis is a life-threatening fungal infection, and its current treatment is toxic and subject to resistance. Drug repurposing represents an interesting approach to find drugs to reduce the toxicity of antifungals. In this study, we evaluated the combination of N-acetylcysteine (NAC) with amphotericin B (AMB) for the treatment of cryptococcosis. We examined the effects of NAC on fungal morphophysiology and on the macrophage fungicidal activity 3 and 24 hours post inoculation. The therapeutic effects of NAC combination with AMB were investigated in a murine model with daily treatments regimens. NAC alone reduced the oxidative burst generated by AMB in yeast cells, but did not inhibit fungal growth. The combination NAC + AMB decreased capsule size, zeta potential, superoxide dismutase activity and lipid peroxidation. In macrophage assays, NAC + AMB did not influence the phagocytosis, but induced fungal killing with different levels of oxidative bursts when compared to AMB alone: there was an increased reactive oxygen species (ROS) after 3 hours and reduced levels after 24 hours. By contrast, ROS remained elevated when AMB was tested alone, demonstrating that NAC reduced AMB oxidative effects without influencing its antifungal activity. Uninfected mice treated with NAC + AMB had lower concentrations of serum creatinine and glutamate-pyruvate transaminase in comparison to AMB. The combination of NAC + AMB was far better than AMB alone in increasing survival and reducing morbidity in murine-induced cryptococcosis, leading to reduced fungal burden in lungs and brain and also lower concentrations of pro-inflammatory cytokines in the lungs. In conclusion, NAC + AMB may represent an alternative adjuvant for the treatment of cryptococcosis.

Topics: Acetylcysteine; Amphotericin B; Animals; Antifungal Agents; Brain; Creatinine; Cryptococcosis; Cryptococcus; Deoxycholic Acid; Disease Models, Animal; Drug Combinations; Drug Repositioning; Female; Kidney; Lung; Macrophages; Mice; Mice, Inbred C57BL; Microbial Sensitivity Tests; Reactive Oxygen Species

Brain infections with

Topics: Amphotericin B; Animals; Antifungal Agents; Cryptococcosis; Cryptococcus neoformans; Disease Models, Animal; Fluconazole; Meningitis, Cryptococcal; Mice

Candida albicans is a major cause of human infections, ranging from relatively simple to treat skin and mucosal diseases to systemic life-threatening invasive candidiasis. Fungal infections treatment faces three major challenges: the limited number of therapeutic options, the toxicity of the available drugs, and the rise of antifungal resistance. In this study, we demonstrate the antifungal activity and mechanism of action of peptides ToAP2 and NDBP-5.7 against planktonic cells and biofilms of C. albicans. Both peptides were active against C. albicans cells; however, ToAP2 was more active and produced more pronounced effects on fungal cells. Both peptides affected C. albicans membrane permeability and produced changes in fungal cell morphology, such as deformations in the cell wall and disruption of ultracellular organization. Both peptides showed synergism with amphotericin B, while ToAP2 also presents a synergic effect with fluconazole. Besides, ToAP2 (6.25 µM.) was able to inhibit filamentation after 24 h of treatment and was active against both the early phase and mature biofilms of C. albicans. Finally, ToAP2 was protective in a Galleria mellonella model of infection. Altogether these results point to the therapeutic potential of ToAP2 and other antimicrobial peptides in the development of new therapies for C. albicans infections.

Topics: Amphotericin B; Animals; Antifungal Agents; Biofilms; Candida albicans; Candidiasis; Cell Membrane Permeability; Cell Wall; Disease Models, Animal; Drug Resistance, Fungal; Drug Synergism; Drug Therapy, Combination; Fluconazole; Humans; Microbial Sensitivity Tests; Moths; Pore Forming Cytotoxic Proteins

Trichosporon asahii is a pathogenic fungus that causes deep mycosis in patients with neutropenia. Establishing an experimental animal model for quantitatively evaluating pathogenicity and developing a genetic recombination technology will help to elucidate the infection mechanism of T. asahii and promote the development of antifungal drugs. Here we established a silkworm infection model with a transgenic T. asahii strain expressing eGFP. Injecting T. asahii into silkworms eventually killed the silkworms. Moreover, the administration of antifungal agents, such as amphotericin B, fluconazole, and voriconazole, prolonged the survival time of silkworms infected with T. asahii. A transgenic T. asahii strain expressing eGFP was obtained using a gene recombination method with Agrobacterium tumefaciens. The T. asahii strain expressing eGFP showed hyphal formation in the silkworm hemolymph. Both hyphal growth and the inhibition of hyphal growth by the administration of antifungal agents were quantitatively estimated by monitoring fluorescence. Our findings suggest that a silkworm infection model using T. asahii expressing eGFP is useful for evaluating both the pathogenicity of T. asahii and the efficacy of antifungal drugs.

Topics: Amphotericin B; Animals; Antifungal Agents; Bombyx; Disease Models, Animal; Fluconazole; Green Fluorescent Proteins; Hyphae; Microbial Sensitivity Tests; Optical Imaging; Organisms, Genetically Modified; Survival Analysis; Trichosporon; Trichosporonosis; Voriconazole

Topics: Amphotericin B; Animals; ATP Binding Cassette Transporter, Subfamily B, Member 1; ATP Binding Cassette Transporter, Subfamily G, Member 2; Blood-Brain Barrier; Brain; Cryptococcus neoformans; Dibenzocycloheptenes; Diketopiperazines; Disease Models, Animal; Heterocyclic Compounds, 4 or More Rings; Humans; Male; Meningitis, Cryptococcal; Mice; Molecular Docking Simulation; Quinolines; Serum Albumin; Tissue Distribution; Triazoles

Fungus is an antigen for bronchial asthma causing allergic bronchopulmonary mycosis (ABPM). As a therapy other than corticosteroids, itraconazole (ITCZ) is known to suppress the allergic inflammation induced by Aspergillus fumigatus (Af). However, the efficacy of liposomal amphotericin B (LAMB) with/without corticosteroid on ABPM is unknown. Mice sensitized to Dermatophagoides farinae (Df) allergen were intranasally infected with Af (DfAf group). After the infection, corticosteroid (dexamethasone (Dex)) was administered for 5 days (DfAf/Dex group). The effects of ITCZ or LAMB with/without Dex were also evaluated. Pathologically, Dex and LAMB combination treatment decreased the allergic inflammation evidently. The bronchoalveolar lavage fluid (BALF) concentrations of IL-5, IL-13, and MIP-2 were significantly elevated in DfAf mice compared with control mice (p < 0.05, each). In DfAf mice, ITCZ and LAMB significantly decreased the elevation of MIP-2 (p < 0.05 vs the DfAf group). The addition of both Dex and LAMB suppressed the MIP-2 elevation in DfAf mice (p < 0.05 vs the Df/Af/Dex/LAMB group), but the addition of Dex and ITCZ did not (DfAf/Dex/ITCZ group). None of Dex, ITCZ, or LAMB decreased pulmonary IL-13 concentration. It was suggested that combination of antifungal drugs and corticosteroid enhanced the suppressing effect of airway inflammations. This finding will give a hope for the treatment of severe fungus-related asthma.

Topics: Adrenal Cortex Hormones; Amphotericin B; Animals; Anti-Inflammatory Agents; Antifungal Agents; Aspergillosis, Allergic Bronchopulmonary; Aspergillus fumigatus; Dexamethasone; Disease Models, Animal; Drug Therapy, Combination; Itraconazole; Mice

Following a fatal case of Cryptococcus neoformans meningitis in a child with X-linked hyper-immunoglobulin M syndrome (XHIGM), we evaluated the fungal isolate in an experimental infection in a mouse model with respect to microbiology, epidemiology, virulence and response to therapy. The minimum inhibitory concentrations for antifungals in the susceptibility test were 0.5mg/L for amphotericin B, 4.0mg/L for fluconazole and 0.12mg/L for voriconazole. Evaluation of pathogenicity by means of an experimental infection in BALB/c mice showed that fungus isolated from the blood and cerebrospinal fluid of the child was able to disseminate, reaching the spleen, lungs and brain, where it caused significant macroscopic alterations in the size and texture of each organ. Treatment of infected mice with amphotericin B reduced the fungal load in the spleen and lungs, but not in the brain.

Topics: Amphotericin B; Animals; Antifungal Agents; Child, Preschool; Cryptococcus neoformans; Disease Models, Animal; Fatal Outcome; Humans; Hyper-IgM Immunodeficiency Syndrome, Type 1; Male; Meningitis, Cryptococcal; Mice; Mice, Inbred BALB C; Microbial Sensitivity Tests; Tomography, X-Ray Computed

Topical application of poorly water-soluble antibiotics cannot achieve the desired therapeutic concentration within cornea. The purpose of this study was to fabricate, characterize and evaluate in-vivo effectiveness of amphotericin B (AmB) containing microneedle ocular patch (MOP) against fungal keratitis. MOP containing free or liposomal AmB was fabricated using micromolding technique to mimic contact lens. MOPs were prepared using dissolvable polymeric matrix including polyvinyl alcohol and polyvinyl pyrrolidone. AmB loaded MOP were studied for their physical and mechanical properties, drug loading and dissolution rate, corneal insertion and drug permeability. MOP loaded with 100 µg AmB had a compression strength of 35.1 ± 6.7 N and required an insertional force of 1.07 ± 0.17 N in excised human cornea. Ex-vivo corneal permeation studies revealed significant enhancement in AmB corneal retention with the application of MOP compared with free AmB or liposomal AmB application. Furthermore, AmB loaded MOP application significantly (P < 0.05) reduced the Candida albicans load within cornea as evaluated in both ex-vivo model and in-vivo rabbit infection model. Histological examination showed that AmB MOP treatment improved the epithelial and stromal differentiation of corneal membrane. AmB containing MOPs can be developed as minimally invasive corneal delivery device for effective treatment of fungal keratitis.

Topics: Administration, Ophthalmic; Amphotericin B; Animals; Antifungal Agents; Candida albicans; Candidiasis; Compressive Strength; Disease Models, Animal; Dosage Forms; Drug Compounding; Drug Delivery Systems; Eye Infections, Fungal; Humans; Keratitis; Male; Miniaturization; Needles; Permeability; Phosphatidylcholines; Polyvinyl Alcohol; Povidone; Rabbits

Mucorales can cause cutaneous to deep-seated infections, mainly in the immunocompromised host, resulting in high mortality rates due to late and inefficient treatment. In this study, Galleria mellonella larvae were evaluated as a heterologous invertebrate host to study pathogenicity of clinically relevant mucormycetes (Rhizopus spp., Rhizomucor spp., Lichtheimia spp., Mucor spp.). All tested species were able to infect G. mellonella larvae. Virulence potential was species-specific and correlated to clinical relevance. Survival of infected larvae was dependent on (a) the species (growth speed and spore size), (b) the infection dose, (c) the incubation temperature, (d) oxidative stress tolerance, and (e) iron availability in the growth medium. Moreover, we exploited the G. mellonella system to determine antifungal efficacy of liposomal amphotericin B, posaconazole, isavuconazole, and nystatin-intralipid. Outcome of in vivo treatment was strongly dependent upon the drug applied and the species tested. Nystatin-intralipid exhibited best activity against Mucorales, followed by posaconazole, while limited efficacy was seen for liposomal amphotericin B and isavuconazole. Pharmacokinetic properties of the tested antifungals within this alternative host system partly explain the limited treatment efficacy. In conclusion, G. mellonella represents a useful invertebrate infection model for studying virulence of mucormycetes, while evaluation of treatment response was limited.

Topics: Amphotericin B; Animals; Antifungal Agents; Disease Models, Animal; Drug Resistance, Fungal; Larva; Lepidoptera; Microbial Sensitivity Tests; Mucor; Mucorales; Mucormycosis; Nitriles; Pyridines; Rhizopus; Triazoles; Virulence

Naegleria fowleri is the causative agent of primary amoebic meningoencephalitis (PAM), which is fatal in >97% of cases. In this study, we aimed to identify new, rapidly acting drugs to increase survival rates. We conducted phenotypic screens of libraries of Food and Drug Administration-approved compounds and the Medicines for Malaria Venture Pathogen Box and validated 14 hits (defined as a 50% inhibitory concentration of <1 μM). The hits were then prioritized by assessing the rate of action and efficacy in combination with current drugs used to treat PAM. Posaconazole was found to inhibit amoeba growth within the first 12 hours of exposure, which was faster than any currently used drug. In addition, posaconazole cured 33% of N. fowleri-infected mice at a dose of 20 mg/kg and, in combination with azithromycin, increased survival by an additional 20%. Fluconazole, which is currently used for PAM therapy, was ineffective in vitro and vivo. Our results suggest posaconazole could replace fluconazole in the treatment of PAM.

Topics: Amphotericin B; Animals; Antiprotozoal Agents; Azithromycin; Central Nervous System Protozoal Infections; Disease Models, Animal; Drug Combinations; Drug Discovery; Drug Synergism; Female; Fluconazole; Humans; Inhibitory Concentration 50; Mice; Naegleria fowleri; Phenotype; Time Factors; Triazoles; United States; United States Food and Drug Administration

Topics: Aminopyridines; Amphotericin B; Animals; Antifungal Agents; Coccidioides; Disease Models, Animal; Female; Fluconazole; Isoxazoles; Mice; Mice, Inbred C57BL; Microbial Sensitivity Tests; Pneumonia; Prodrugs; Triazoles

Cutaneous leishmaniasis (CL) is an infectious, parasitic disease caused by the protozoan Leishmania. Amphotericin B (AMB) is a macrolide polyene antibiotic presenting potent antifungal and antileishmanial activity, but due to poor water solubility at physiological pH, side effects, and toxicity, its therapeutic efficiency is limited. In the present study, poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) loaded with AMB were generated to reduce drug toxicity and facilitate localized delivery over a prolonged time. AMB NPs were characterized for particle size, zeta potential, polydispersity index, and degree of aggregation. In vitro assessments demonstrated its sustained activity against Leishmania major promastigotes and parasite-infected macrophages. A single intralesional administration to infected BALB/c mice revealed that AMB NPs were more effective than AMB deoxycholate in terms of reducing lesion area. Taken together, these findings suggest that AMB NPs improve AMB delivery and can be used for local treatment of CL.

Topics: Administration, Topical; Amphotericin B; Animals; Antiprotozoal Agents; Disease Models, Animal; Drug Carriers; Humans; Leishmania major; Leishmaniasis, Cutaneous; Mice; Mice, Inbred BALB C; Nanoparticles; Particle Size; Polyesters; Polyglycolic Acid; THP-1 Cells

To find novel amphotericin B (AmB) derivatives with high therapeutic potential, low toxicity, and water solubility, a series of nine N-substituted AmB derivatives were evaluated for their antifungal activity using the broth dilution method and for their hemolytic toxicity with sterile defibrinated sheep blood. Qualitative screening of the effect of the derivatives on two reference Candida albicans strains and of their solubility was performed based on the value of n (n is a positive integer), resulting in the identification of an optimal compound, NH

Topics: Amphotericin B; Animals; Antifungal Agents; Candida albicans; Cell Survival; Cytological Techniques; Disease Models, Animal; Erythrocytes; HEK293 Cells; Hemolysis; Humans; Microbial Sensitivity Tests; Poisoning; Sheep; Solubility

Topics: Amphotericin B; Animals; Antiprotozoal Agents; Disease Models, Animal; Female; Flow Cytometry; Hep G2 Cells; Humans; Inhibitory Concentration 50; Leishmania infantum; Leishmania mexicana; Leishmaniasis, Cutaneous; Leishmaniasis, Visceral; Liver; Mice; Mice, Inbred BALB C; Naphthoquinones; Parasite Load; Plant Extracts; Random Allocation; RAW 264.7 Cells; Skin; Spleen; Tabebuia

The treatment against leishmaniasis presents problems, since the currently used drugs are toxic and/or have high costs. In addition, parasite resistance has increased. As a consequence, in this study, a chloroquinolin derivative, namely 7-chloro-N,N-dimethylquinolin-4-amine or GF1059, was in vitro and in vivo tested against Leishmania parasites. Experiments were performed to evaluate in vitro antileishmanial activity and cytotoxicity, as well as the treatment of infected macrophages and the inhibition of infection using pre-treated parasites. This study also investigated the GF1059 mechanism of action in L. amazonensis. Results showed that the compound was highly effective against L. infantum and L. amazonensis, presenting a selectivity index of 154.6 and 86.4, respectively, against promastigotes and of 137.6 and 74.3, respectively, against amastigotes. GF1059 was also effective in the treatment of infected macrophages and inhibited the infection of these cells when parasites were pre-incubated with it. The molecule also induced changes in the parasites' mitochondrial membrane potential and cell integrity, and caused an increase in the reactive oxygen species production in L. amazonensis. Experiments performed in BALB/c mice, which had been previously infected with L. amazonensis promastigotes, and thus treated with GF1059, showed that these animals presented significant reductions in the parasite load when the infected tissue, spleen, liver, and draining lymph node were evaluated. GF1059-treated mice presented both lower parasitism and low levels of enzymatic markers, as compared to those receiving amphotericin B, which was used as control. In conclusion, data suggested that GF1059 can be considered a possible therapeutic target to be tested against leishmaniasis.

Topics: Amphotericin B; Animals; Antiprotozoal Agents; Chloroquinolinols; Disease Models, Animal; Erythrocytes; Female; Inhibitory Concentration 50; Leishmania infantum; Leishmania mexicana; Leishmaniasis, Cutaneous; Leishmaniasis, Visceral; Liver; Lymph Nodes; Macrophages; Macrophages, Peritoneal; Membrane Potential, Mitochondrial; Mice; Mice, Inbred BALB C; Parasite Load; Reactive Oxygen Species; Spleen

Chronic stress-induced decline in microglia in the hippocampus is a newly hypothesized mechanism of depression, and reversal of this decline by microglial activators has been shown to suppress depression-like behaviors in mice. This suggests that activation of immune cells in the hippocampus may be a potential strategy for depression therapy. Since amphotericin B, an anti-fungal medication, is known to activate macrophages and microglia, we investigated whether conventional amphotericin B or its liposomal form displays antidepressant activity. Our results showed that both amphotericin B and its liposomal form at various doses induced obvious depression-like behaviors in naïve mice, likely owing to increased serum interleukin-6 (IL-6) and IL-1β levels. However, under stressed conditions, amphotericin B liposome, but not amphotericin B itself, reversed chronic unpredictable stress (CUS)-induced increase in immobility time in the tail suspension test and forced swim test as well as CUS-induced decrease in sucrose intake in the sucrose preference test and the time spent in the center region of the open field test in a dose-dependent manner. Immunofluorescence analysis showed that amphotericin B liposome reversed the CUS-induced decline in dentate gyrus (DG) microglia, and inhibition or ablation of microglia in the hippocampus by minocycline (40 mg/kg) or PLX3397 pre-treatment (290 mg/kg) abrogated the antidepressant effect of the amphotericin B liposome in CUS-treated mice. These results not only identify a novel pharmacological effect of amphotericin B liposome, but further support the notion that microglial activation in the hippocampus is a potential strategy for depression therapy.

Topics: Amphotericin B; Animals; Antidepressive Agents; Behavior, Animal; Depression; Disease Models, Animal; Hindlimb Suspension; Interleukin-1beta; Interleukin-6; Liposomes; Mice; Microglia; Stress, Psychological; Swimming

Paracoccidioidomycosis (PCM) is a neglected disease present in Latin America with difficulty in treatment and occurrence of serious sequelae. Thus, the development of alternative therapies is imperative. In the current work, two oxadiazole compounds (LMM5 and LMM11) presented fungicidal activity against Paracoccidioides spp. The minimum inhibitory and fungicidal concentration values ranged from 1 to 32 μg/mL, and a synergic effect was observed for both compounds when combined with Amphotericin B. LMM5 and LMM11 were able to reduce CFU counts (≥2 log10) on the 5th and 7th days of time-kill curve, respectively. The fungicide effect was confirmed by fluorescence microscopy (FUN-1/FUN-2). The hippocratic screening and biochemical analysis were performed in Balb/c male mice that received a high dose of each compound, and the compounds showed no in vivo toxicity. The treatment of experimental PCM with the new oxadiazoles led to significant reduction in CFU (≥1 log10). Histopathological analysis of the groups treated exhibited control of inflammation, as well as preserved lung areas. These findings suggest that LMM5 and LMM11 are promising hits structures, opening the door for implementing new PCM therapies.

Topics: Amphotericin B; Animals; Antifungal Agents; Colony Count, Microbial; Disease Models, Animal; Drug Synergism; Histocytochemistry; Lung; Male; Mice, Inbred BALB C; Microbial Sensitivity Tests; Microbial Viability; Oxadiazoles; Paracoccidioides; Paracoccidioidomycosis; Treatment Outcome

Candida albicans causes a high mortality rate in immunocompromised individuals, but the increased drug resistance challenges the current antifungal therapeutics. Fluphenazine (FPZ), a commonly used antipsychotic medication, can induce the expression of drug efflux pumps in C. albicans and, thus, may interfere with the therapeutic efficacy of antifungals, such as fluconazole (FLC) and amphotericin B (AmB). Here, we investigated the combined effects of FLC/FPZ and AmB/FPZ against C. albicans in vitro and in a systemic candidiasis mouse model. The antifungal activity of FLC was significantly reduced when supplemented with FPZ. The inhibitory effects of FLC on the expression of the Candida virulence-related genes ALS3 and HWP1 were antagonized by FPZ. However, FPZ enhanced the susceptibility of C. albicans to AmB and further downregulated the expression of ALS3 and HWP1 in a synergistic manner with AmB. FPZ also enhanced the gene expression of ERG11, a key gene of the ergosterol biosynthesis pathway that has been associated with the activities of both FLC and AmB. In our mammalian infection model, mice treated with FLC/FPZ showed notably poor living status and increased fungal burden in their kidneys and brains compared with those treated with FLC alone. Conversely, the combined application of AmB/FPZ significantly improved the survival rate, attenuated the weight loss and reduced the organ fungal burdens of the infected mice. These data suggest that FPZ antagonized the therapeutic efficacy of FLC but enhanced the antifungal activity of AmB in the treatment of candidiasis.

Topics: Amphotericin B; Animal Structures; Animals; Antifungal Agents; Antipsychotic Agents; Candida albicans; Candidiasis; Colony Count, Microbial; Disease Models, Animal; Drug Interactions; Fluconazole; Fluphenazine; Gene Expression Profiling; Gene Expression Regulation, Fungal; Mice; Treatment Outcome

Approximately 180,000 people worldwide die from cryptococcosis each year, probably due to the ineffectiveness and toxicity of drugs currently available to treat the disease. Amphotericin B (AMB) is effective for killing the fungus, but has serious adverse effects linked to excessive production of reactive oxygen species which compromise renal function. Pioglitazone (PIO) is a peroxisome proliferator-activated receptor-γ agonist widely repositioned as an adjuvant of various drugs that have toxic effects due to its antioxidant and anti-inflammatory effects. This study evaluated PIO in combination with AMB for the treatment of cryptococcosis. PIO was found to reduce serum creatinine and glutamic-oxalacetic transaminase levels in mice treated with PIO+AMB. In vitro, PIO was able to control harmful oxidative bursts induced by AMB without compromising the antifungal effect. In vivo, PIO+AMB increased the survival rate compared with AMB alone, and improved the morbidity of the animals. PIO+AMB was more efficient than AMB alone for inhibiting fungal transmigration from the lungs to the brain, and killing yeasts that reached the central nervous system, avoiding the establishment of meningoencephalitis. In a phagocytosis assay, PIO did not influence the engulfment and fungicidal activity of macrophages induced by AMB, but reduced the oxidative bursts after the reduction of fungal burden, pointing to control of the pathogen without leading to excessive stress which can be damaging to the host. In conclusion, PIO+AMB was found to ameliorate cryptococcosis in a murine model, indicating that it is a promising therapeutic adjuvant for combating and controlling this fungal infection.

Topics: Amphotericin B; Animals; Antifungal Agents; Antioxidants; Cryptococcosis; Cryptococcus gattii; Disease Models, Animal; Drug Repositioning; Drug Therapy, Combination; Mice, Inbred C57BL; Pioglitazone; Survival Analysis; Treatment Outcome

To evaluate a new corneal cold storage medium including an antimycotic tablet (Kerasave, AL.CHI.MI.A. S.r.l.).. Kerasave and tryptone soy broth (control) were inoculated with 10 and 10 colony-forming units (CFU)/mL of 6 Candida isolates (Candida albicans [n = 4], Candida tropicalis [n = 1], and Candida glabrata [n = 1]). Minimum inhibitory concentrations (MICs) were determined using amphotericin B Etest strips. Sterile porcine corneas contaminated with 10 CFU/mL of each isolate were incubated in Kerasave and control at 4°C. Growth rate and Log10 reduction at 4°C at different time intervals were determined for liquid samples and tissue homogenates. Kerasave biocompatibility was assessed according to ISO 10993-5 and ISO 10993-10.. No C. albicans or C. tropicalis colonies were recovered from Kerasave inoculated with 10 CFU/mL after incubation for 3 days at 4°C. C. glabrata was inhibited but not killed after 3 days at 4°C. Four of the 6 strains contaminated with 10 CFU/mL demonstrated a significant ≥ 3 Log10 reduction in media and tissue homogenates within 5 days as compared to controls (p < 0.01). Amphotericin B MICs ranged from 0.19 to 0.38 μg/mL for C. albicans (n = 3) and C. tropicalis (n = 1). C. glabrata showed reduced susceptibility (0.5 μg/mL) and 1 C. albicans was resistant to amphotericin B (≥ 1 μg/mL). Kerasave was not cytotoxic, irritating, or sensitizing according to the ISO standards.. Kerasave showed high antifungal efficacy against susceptible fungal strains at 4°C in the presence and absence of corneal tissue. Resistant strains to amphotericin B were not eliminated by Kerasave. Kerasave is not cytotoxic, irritating, or sensitizing.

Topics: Amphotericin B; Animals; Antifungal Agents; Candida; Candidiasis; Cornea; Disease Models, Animal; Eye Infections, Fungal; Keratitis; Microbial Sensitivity Tests; Organ Preservation; Organ Preservation Solutions; Swine

In severe cases of sporotrichosis, it is recommended to use amphotericin B deoxycholate (D-AMB) or its lipid formulations and/or in association with itraconazole (ITC). Our aim was to evaluate the antifungal efficacy of a poly-aggregated amphotericin B (P-AMB), a nonlipid formulation, compared with D-AMB on systemic sporotrichosis caused by Sporothrix brasiliensis. In vitro assays showed that Sporothrix schenckii sensu stricto and S. brasiliensis yeast clinical isolates were susceptible to low concentrations of P-AMB and D-AMB. Although P-AMB presented a higher minimal inhibitory concentration (MIC) compared to D-AMB, its cytotoxic effect on renal cells and erythrocytes was lower. For the in vivo assays, male BALB/c mice were intravenously infected with S. brasiliensis yeasts, and P-AMB or D-AMB was administered 3 days post-infection. The efficacy of five therapeutic regimens was tested: intravenous monotherapy with P-AMB or D-AMB, intravenous pulsed-therapy with P-AMB or D-AMB, and intravenous therapy with P-AMB, followed by oral ITC. These treatments increased murine survival and controlled the fungal burden in the liver, spleen, lungs, and kidneys. However, only D-AMB monotherapy or the pulsed-therapies with D-AMB or P-AMB led to 100% survival of the mice 45 days post-infection; only pulsed administration of D-AMB was able to control the fungal load in all organs 45 days post-infection. Accordingly, the histopathological findings showed reductions in the fungal burden and inflammatory reactions in these treatment regimens. Together, our results suggest that the P-AMB formulation could be considered as an alternative drug to D-AMB for treating disseminated sporotrichosis.

Topics: Amphotericin B; Animals; Antifungal Agents; Cell Survival; Colony Count, Microbial; Deoxycholic Acid; Disease Models, Animal; Drug Combinations; Male; Mice; Mice, Inbred BALB C; Microbial Sensitivity Tests; Sporothrix; Sporotrichosis; Survival Rate

Mycetoma is a tropical neglected disease characterized by large subcutaneous lesions in which the causative organisms reside in the form of grains. The most common causative agent is Madurella mycetomatis. Antifungal therapy often fails due to these grains, but to identify novel treatment options has been difficult since grains do not form in vitro. We recently used Galleria mellonella larvae to develop an in vivo grain model. In the current study, we set out to determine the therapeutic efficacy of commonly used antifungal agents in this larval model. Pharmacokinetics of ketoconazole, itraconazole, voriconazole, posaconazole, amphotericin B, and terbinafine were determined in the hemolymph of G. mellonella larvae. Antifungal therapy was given either therapeutically or prophylactic on three consecutive days in therapeutically equivalent dosages. Survival was monitored for 10 days and colony-forming units (cfu) and melanization were determined on day 3. Measurable concentrations of antifungal agents were found in the hemolymph of the larvae. None of the azole antifungal agents prolonged survival when given therapeutically or prophylactically. Amphotericin B and terbinafine did prolong survival, even at concentrations below the minimal inhibitory concentration of M. mycetomatis. The cfu and melanization did not differ between any of the treated groups and phosphate-buffered saline (PBS) treated groups. Grains were still present in surviving larvae but appeared to be encapsulated. This study demonstrated for the first time a comparison between the efficacy of different antifungal agents toward grains of M. mycetomatis. It appeared that amphotericin B and terbinafine were able to prolong larval survival.

Topics: Amphotericin B; Animals; Antifungal Agents; Disease Models, Animal; Larva; Madurella; Microbial Sensitivity Tests; Moths; Terbinafine

Cryptococcosis is a subacute or chronic disease. For many years, amphotericin B has been used in severe fungal infections. Voriconazole is a triazole with high bioavailability, a large distribution volume, and excellent penetration of the central nervous system (CNS). The objective of this study was to evaluate the production of pro-inflammatory cytokines in the lungs during an experimental infection caused by C. neoformans in murine model (SCID) that was treated with amphotericin B and voriconazole. After intravenous inoculation with 3.0×10

Topics: Amphotericin B; Animals; Antifungal Agents; Cryptococcosis; Cryptococcus neoformans; Cytokines; Disease Models, Animal; Drug Therapy, Combination; Inflammation; Lung; Lung Diseases, Fungal; Mice; Severe Combined Immunodeficiency; Voriconazole

To fabricate, characterize and evaluate 3-O-sn-Phosphatidyl-L-serine (PhoS) anchored PLGA nanoparticles for macrophage targeted therapeutic intervention of VL.. PLGA-AmpB NPs were prepared by well-established nanoprecipitation method and decorated with Phos by thin film hydration method. Physico-chemical characterization of the formulation was done by Zetasizer nano ZS and atomic force microscopy.. The optimized formulation (particle size, 157.3 ± 4.64 nm; zeta potential, - 42.51 ± 2.11 mV; encapsulation efficiency, ∼98%) showed initial rapid release up to 8 h followed by sustained release until 72 h. PhoS generated 'eat-me' signal driven augmented macrophage uptake, significant increase in in-vitro (with ∼82% parasite inhibition) and in-vivo antileishmanial activity with preferential accumulation in macrophage rich organs liver and spleen were found. Excellent hemo-compatibility justified safety profile of developed formulation in comparison to commercial formulations.. The developed PhoS-PLGA-AmpB NPs have improved efficacy, and necessary stability which promisingly put itself as a better alternative to available commercial formulations for optimized treatment of VL.

Topics: Amphotericin B; Animals; Antiprotozoal Agents; Cell Line; Delayed-Action Preparations; Disease Models, Animal; Drug Carriers; Drug Compounding; Drug Evaluation, Preclinical; Drug Stability; Humans; Leishmania donovani; Leishmaniasis, Visceral; Macrophages; Male; Mice; Nanoparticles; Phosphatidylserines; Polylactic Acid-Polyglycolic Acid Copolymer; Rats; Rats, Wistar; Treatment Outcome

Annual global deaths from cryptococcal meningitis (CM) are estimated at 180 000 and mortality is as high as 30%, even with optimal therapy. VT-1598 is a novel fungal CYP51 inhibitor with potent intrinsic antifungal activity against Cryptococcus. We report here VT-1598's in vivo antifungal activity in a murine model of CM.. Single-dose plasma and brain pharmacokinetics in mice and MIC for Cryptococcus neoformans H99 were determined prior to efficacy studies. Short-course monotherapy and combination doses were explored with the endpoint of brain fungal burden. A survival study was also conducted using monotherapy treatment with fungal burden measured after a 6 day drug washout.. Oral doses of VT-1598 had good plasma and brain exposure and resulted in significant (P < 0.0001) and dose-dependent reductions in brain fungal burden, reaching a 6 log10 reduction. Unlike either positive drug control (fluconazole or liposomal amphotericin B), both mid and high doses of VT-1598 reduced fungal burden to below levels measured at the start of treatment. When VT-1598 was dosed in the survival study, no VT-1598-treated animal succumbed to the infection. Whereas fluconazole showed a 2.5 log10 increase in fungal burden after the 6 day washout, the VT-1598 mid- and high-dose animals showed almost no regrowth (<0.5 log10). In a separate fungal burden study using suboptimal doses of VT-1598 and liposomal amphotericin B to probe for combination effects, each combination had a positive effect relative to corresponding monotherapies.. These pre-clinical in vivo data strongly support clinical investigation of VT-1598 as a novel therapy for this lethal infection.

Topics: 14-alpha Demethylase Inhibitors; Administration, Oral; Amphotericin B; Animals; Antifungal Agents; Colony Count, Microbial; Cryptococcus neoformans; Disease Models, Animal; Drug Therapy, Combination; Meningitis, Cryptococcal; Mice; Microbial Sensitivity Tests; Survival Analysis; Treatment Outcome

The present work assesses the effect in vitro of combining the antiretroviral drug nelfinavir (NFV), a drug used against HIV but also a strong in vitro inhibitor of the growth of Leishmania promastigotes and amastigotes, with amphotericin B or miltefosine on different strains of Leishmania infantum. The isobolograms revealed a synergistic effect for both combinations, with a fractional inhibitory concentration index (∑FIC) <0.5. The ∑FIC values obtained with reference strain MCAN/ES/98/LLM-724 were 0.25 ± 0.1 (95% CI: 0.178-0.322) for the combination NFV+AMB and 0.48 ± 0.2 (95% CI: 0.377-0.573) for the combination NFV+MTF. The effect of NFV on visceral leishmaniasis induced by L. infantum in BALB/c mice was also examined, and the results confirmed a leishmanicidal effect when administered alone, with approximately 60% (P<0.05) reductions in the liver and spleen parasite burdens. This is the first time this has been reported in an in vivo model. A significant reduction in the liver (77%; P<0.01) and spleen (76%; P<0.01) parasite burdens was also observed for NFV+MTF compared with those obtained when these drugs were used alone. This indicates that such combinations may be useful treatment options in patients with visceral leishmaniasis who are also infected with HIV.

Topics: Amphotericin B; Animals; Antiprotozoal Agents; Cell Survival; Disease Models, Animal; Drug Synergism; Humans; Leishmania infantum; Leishmaniasis, Visceral; Liver; Male; Mice, Inbred BALB C; Nelfinavir; Parasite Load; Phosphorylcholine; Spleen; Treatment Outcome

We determined micafungin, caspofungin and amphotericin B (AMB) minimum inhibitory concentration (MICs) and killing rates in RPMI-1640 and in RPMI-1640 with 50% serum against three Candida krusei bloodstream isolates. MIC ranges in RPMI-1640 were 0.125-0.25, 0.25 and 0.125-0.5 mg/L, in RPMI-1640 with 50% serum, MICs were 64-128-, 8- and 4-16-fold higher, respectively. In RPMI-1640 micafungin and caspofungin at 1, 4, 16 and 32 mg/L as well as AMB at 2 mg/L were fungicidal against all isolates in ≤3.96, ≤4.42 and 14.96 h, respectively. In RPMI-1640 with 50% serum, caspofungin was fungicidal for all isolates only at 32 mg/L, micafungin and AMB were fungistatic. In neutropenic mice, 5 mg/kg caspofungin and 1 mg/kg AMB were ineffective against two of the three isolates. Thus, in vivo efficacy of echinocandins and AMB is weak or absent against C. krusei. Prescribers treating C. krusei infections with echinocandins should watch out for clinical resistance and therapeutic failure.

Topics: Amphotericin B; Animals; Antifungal Agents; Candida; Candidemia; Caspofungin; Disease Models, Animal; Drug Evaluation, Preclinical; Humans; Micafungin; Microbial Sensitivity Tests

The efficacy of liposomal amphotericin B and voriconazole was evaluated against the systemic infection by Fusarium oxysporum species complex or Fusarium keratoplasticum. Although MIC values were within the epidemiological cutoff values (ECVs) recently stablished for Fusarium spp., no efficacy was obtained, indicating that ECVs for Fusarium are not relevant for in vivo efficacy.

Topics: Amphotericin B; Animals; Antifungal Agents; Disease Models, Animal; Fusariosis; Fusarium; Mice; Voriconazole

The formation of Candida biofilms on implanted medical devices is crucial to the development of infections and an important clinical problem because of elevated resistance to antifungals. The aim of this study was to compare the in vitro activity of liposomal amphotericin B (L-AMB) and micafungin (MCFG) against four species of Candida biofilms, and the efficacy of systemic plus lock therapy with L-AMB and MCFG in a Candida biofilm-associated catheter infection model. An XTT-reduction assay was used to measure the metabolic activity of the biofilms to evaluation of in vitro antibiofilm activity. MCFG had better in vitro activity than L-AMB against Candida glabrata biofilms, whereas L-AMB had better activity than MCFG against Candida albicans and Candida tropicalis biofilms. L-AMB and MCFG had comparable efficacy against Candida parapsilosis biofilms. In an in vitro lock therapy model, 2 mg/ml L-AMB, unlike 2 mg/ml MCFG, significantly reduced the metabolic activity of all the strains of biofilms by >96%. Systemic and intraluminal lock treatment with L-AMB for 3-days resulted in more than about 2 log

Topics: Amphotericin B; Animals; Antifungal Agents; Biofilms; Candida albicans; Candida glabrata; Candida parapsilosis; Candida tropicalis; Catheter-Related Infections; Disease Models, Animal; Humans; Male; Micafungin; Mice; Mice, Inbred Strains; Treatment Outcome

To determine whether combination therapy would improve therapeutic outcome in eumycetoma caused by Madurella mycetomatis.. Survival, colony-forming units (CFU), melanisation and histopathology in M. mycetomatis-infected Galleria mellonella larvae treated with amphotericin B, itraconazole, terbinafine or combinations thereof were determined.. Compared to larvae treated with 5% glucose, enhanced survival was obtained when M. mycetomatis-infected larvae were treated with amphotericin B, but not when they were treated with itraconazole or terbinafine. Combination therapy did not increase survival compared to 5% glucose-treated larvae, itraconazole-treated larvae or terbinafine-treated larvae. Compared to amphotericin B monotreatment, a significant decrease in survival was noted when this therapy was combined with either itraconazole or terbinafine. CFU, melanisation and histopathology did not differ between monotherapy, combination therapy or 5% glucose-treated larvae.. Combining different classes of antifungal agents did not enhance the survival of M. mycetomatis-infected G. mellonella larvae. Instead of improving the therapeutic outcome, combining either itraconazole or terbinafine with amphotericin B resulted in significantly lower survival rates of infected larvae than amphotericin B monotherapy. This experimental study does not provide support for the use of combined amphotericin B and itraconazole, combined itraconazole and terbinafine or combined terbinafine and amphotericin B and should be confirmed in other animal models.

Topics: Amphotericin B; Animals; Antifungal Agents; Disease Models, Animal; Drug Therapy, Combination; Itraconazole; Larva; Madurella; Moths; Mycetoma; Naphthalenes; Terbinafine

Infective endocarditis is a disease characterised by heart valve lesions, which exhibit extracellular matrix proteins that act as a physical barrier to prevent the passage of antimicrobial agents. The genus Candida has acquired clinical importance given that it is increasingly being isolated from cases of nosocomial infections.. To evaluate the activity of caspofungin compared to that of liposomal amphotericin B against Candida albicans in experimental infective endocarditis.. Wistar rats underwent surgical intervention and infection with strains of C. albicans to develop infective endocarditis. Three groups were formed: the first group was treated with caspofungin, the second with liposomal amphotericin B, and the third received a placebo. In vitro sensitivity was first determined to further evaluate the effect of these treatments on a rat experimental model of endocarditis by semiquantitative culture of fibrinous vegetations and histological analysis.. Our semiquantitative culture of growing vegetation showed massive C. albicans colonisation in rats without treatment, whereas rats treated with caspofungin showed significantly reduced colonisation, which was similar to the results obtained with liposomal amphotericin B.. The antifungal activity of caspofungin is similar to that of liposomal amphotericin B in an experimental model of infective endocarditis caused by C. albicans.

Topics: Amphotericin B; Animals; Antifungal Agents; Candida albicans; Candidiasis; Caspofungin; Disease Models, Animal; Echinocandins; Endocarditis; Female; Lipopeptides; Rats; Rats, Wistar

Topics: Amphotericin B; Animals; Antiprotozoal Agents; Chloroquine; Disease Models, Animal; Drug Combinations; Female; Leishmania major; Leishmania mexicana; Leishmaniasis, Cutaneous; Mice; Mice, Inbred BALB C; Parasite Load; Parasitic Sensitivity Tests; Paromomycin; Phosphorylcholine

Cryptococcus spp., the causative agents of cryptococcosis, are responsible for deaths of hundreds of thousands of people every year worldwide. The drawbacks of available therapeutic options are aggravated by the increased resistance of yeast to the drugs, resulting in inefficient therapy. Also, the antifungal 5FC is not available in many countries. Therefore, a combination of antifungal drugs may be an interesting option, but in vitro and theoretical data point to the possible antagonism between the main antifungals used to treat cryptococcosis, i.e., fluconazole (FLC), and amphotericin B (AMB). Therefore, in vivo studies are necessary to test the above hypothesis. In this study, the efficacy of FLC and AMB at controlling C. gattii infection was evaluated in a murine model of cryptococcosis caused by C. gattii. The infected mice were treated with FLC + AMB combinations and showed a significant improvement in survival as well as reduced morbidity, reduced lung fungal burden, and the absence of yeast in the brain when FLC was used at higher doses, according to the Tukey test and principal component analysis. Altogether, these results indicate that combinatorial optimization of antifungal therapy can be an option for effective control of cryptococcosis.

Topics: Amphotericin B; Animals; Antifungal Agents; Brain; Cryptococcosis; Cryptococcus gattii; Disease Models, Animal; Drug Therapy, Combination; Fluconazole; Humans; Lung; Mice; Microbial Sensitivity Tests; Treatment Outcome

To compare the safety and efficacy of intravitreal anidulafungin injection with voriconazole and amphotericin B (Amp B) in an experimental Candida endophthalmitis (CE) model.. Total clinical scores were significantly different between treatment groups and the control group (p < 0.05). On day 7 of the therapy, clinical scores of the anidulafungin group were found to be significantly lower when compared with the other therapy groups, while a significant improvement was observed in the eyes of rabbits in the anidulafungin group (p < 0.05). Also, microbiological scores of the anidulafungin group were lower than those of the control group (p < 0.05). Histopathological scores of the anidulafungin treatment group were significantly better than the voriconazole and control groups. Inflammation was evidently suppressed and marked retinal toxicity was not observed with anidulafungin.. This is the first study comparing the efficacy of anidulafungin with other antifungal agents. In this CE model, an intravitreal single dose of anidulafungin was shown to be noninferior to voriconazole and Amp B. As an alternative to Amp B or voriconazole, intravitreal anidulafungin is suggested as an effective antifungal agent for the treatment of CE.

Topics: Amphotericin B; Anidulafungin; Animals; Antifungal Agents; Candida albicans; Candidiasis; Conjunctiva; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Therapy, Combination; Echinocandins; Endophthalmitis; Eye Infections, Fungal; Intravitreal Injections; Iris; Male; Rabbits; Vitreous Body; Voriconazole

Glioblastoma (GBM) is an aggressive brain cancer with a poor prognosis. The use of immune therapies to treat GBM has become a promising avenue of research. It was shown that amphotericin B (Amp B) can stimulate the innate immune system and suppress the growth of brain tumor initiating cells (BTICs). However, it is not feasible to use histopathology to determine immune activation in patients. We developed an MRI technique that can rapidly detect a therapeutic response in animals treated with drugs that stimulate innate immunity. Ultra-small iron oxide nanoparticles (USPIOs) are MRI contrast agents that have been widely used for cell tracking. We hypothesized that the increased monocyte infiltration into brain tumors due to Amp B can be detected using USPIO-MRI, providing an indicator of early drug response.. We implanted human BTICs into severe combined immunodeficient mice and allowed the tumor to establish before treating the animals with either Amp B or vehicle and then imaged them using MRI with USPIO (ferumoxytol) contrast.. After 7 days of treatment, there was a significantly decreased T2* in the tumor of Amp B but not vehicle animals, suggesting that USPIO is carried into the tumor by monocytes. We validated our MRI results with histopathology and confirmed that Amp B-treated animals had significantly higher levels of macrophage/microglia that were colocalized with iron staining in their brain tumor compared with vehicle mice.. USPIO-MRI is a promising method of rapidly assessing the efficacy of anticancer drugs that stimulate innate immunity.

Topics: Amphotericin B; Animals; Anti-Bacterial Agents; Brain Neoplasms; Cell Tracking; Contrast Media; Dextrans; Disease Models, Animal; Humans; Magnetic Resonance Imaging; Magnetite Nanoparticles; Mice; Mice, SCID; Monocytes; Nanoparticles; Neoplastic Stem Cells; Tumor Cells, Cultured; Xenograft Model Antitumor Assays

Cryptococcus albidus and Cryptococcus laurentii are uncommon species of this genus that in recent decades have increasingly caused opportunistic infections in humans, mainly in immunocompromised patients; the best therapy for such infection being unknown. Using a murine model of systemic infection by these fungi, we have evaluated the efficacy of amphotericin B (AMB) at 0.8 mg/kg, administered intravenously, fluconazole (FLC) or voriconazole (VRC), both administered orally, at 25 mg/kg and the combination of AMB plus VRC against three C. albidus and two C. laurentii strains. All the treatments significantly reduced the fungal burden in all the organs studied. The combination showed a synergistic effect in the reduction in fungal load, working better than both monotherapies. The histopathological study confirmed the efficacy of the treatments.

Topics: Administration, Intravenous; Administration, Oral; Amphotericin B; Animals; Antifungal Agents; Cryptococcosis; Cryptococcus; Disease Models, Animal; Drug Synergism; Drug Therapy, Combination; Fluconazole; Immunocompromised Host; Lung; Mice; Microbial Sensitivity Tests; Spleen; Voriconazole

The aim of this work is to design new chitosan conjugates able to self-organize in aqueous solution in the form of micrometer-size platelets. When mixed with amphotericin B deoxycholate (AmB-DOC), micro-platelets act as a drug booster allowing further improvement in AmB-DOC anti-Candida albicans activity.. Micro-platelets were obtained by mixing oleoyl chitosan and α-cyclodextrin in water. The formulation is specifically-engineered for mucosal application by dispersing chitosan micro-platelets into thermosensitive pluronic. These results demonstrate for the first time the ability of flattened chitosan micro-platelets to have synergistic activity with AmB-DOC against C. albicans candidiasis and highlight the importance of rheological and mucoadhesive behaviors of hydrogels in the efficacy of the treatment.

Topics: alpha-Cyclodextrins; Amphotericin B; Animals; Antifungal Agents; Blood Platelets; Candida albicans; Candidiasis; Chemistry, Pharmaceutical; Chitosan; Deoxycholic Acid; Disease Models, Animal; Drug Combinations; Female; Hydrogels; Mice; Mice, Inbred BALB C; Mucous Membrane; Nanoparticles; Poloxamer; Swine

T-2307, a novel arylamidine, exhibits potent broad-spectrum activities against the majority of fungal pathogens. In this study, the antifungal activity of T-2307 against Cryptococcus gattii was evaluated in comparison with those of amphotericin B, fluconazole and voriconazole in vitro and in vivo .. The MICs for 15 clinical isolates were determined according to CLSI guidelines and time-kill studies were performed using C. gattii YF2784. In a murine model for intranasal pulmonary infection caused by C. gattii YF2784, the test compounds were administered once daily for 7 days from 2 h or 14 days post-infection. The viable counts in the lungs and brain were determined at 21 days post-infection.. The MIC range, MIC 50 , MIC 90 and geometric mean MIC of T-2307 were 0.0078-0.0625, 0.0313, 0.0625 and 0.0394 mg/L, respectively. The MIC of T-2307 was significantly lower than those of fluconazole, voriconazole and amphotericin B. T-2307 showed concentration-dependent fungicidal activity at 4 times the MIC or higher. Administration of T-2307 at 2 mg/kg/day, amphotericin B at 1 mg/kg/day and fluconazole at 160 mg/kg/day from 2 h post-infection significantly reduced viable counts in the lungs and brain. However, when the administration was started 14 days post-infection, only T-2307 significantly reduced the viable counts in both the lungs and the brain at 1 mg/kg/day.. T-2307 shows excellent in vitro and in vivo antifungal activities against C. gattii and would be a promising new candidate for the treatment of cryptococcosis.

Topics: Amidines; Amphotericin B; Animals; Antifungal Agents; Brain; Cryptococcosis; Cryptococcus gattii; Cryptococcus neoformans; Disease Models, Animal; Drug Discovery; Drug Resistance, Fungal; Fluconazole; Humans; Lung; Lung Diseases, Fungal; Mice; Microbial Sensitivity Tests; Voriconazole

Systemic fungal infections are an increasingly prevalent health problem, especially among immunocompromised patients. Antifungal drug development lags far behind in comparison to other types of antimicrobial drugs. Current commercially available antifungals are limited by their insufficient potency, side effects, drug-drug interactions, developing drug-resistance, and narrow formulation options. Here, we report the preparation and evaluation of two novel PEG amide conjugates of amphotericin B (AMB (1)): AB1 (4) and AM2 (5). These compounds are nonlabile, they are prepared in only two and three synthetic steps, respectively, and they show antifungal activity against a wide range of clinical fungal isolates. Their toxicity is significantly lower, and their water solubility is up to 5000-fold higher than that of AMB (1). In vivo efficacy studies in a mouse model of systemic candidiasis showed that AM2 (5) successfully cured all the mice at concentrations above 3.5 mg/kg body weight. In conclusion, these properties make AB1 (4) and AM2 (5) promising candidates for clinical use.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillus; Candida; Candidiasis; Cell Survival; Disease Models, Animal; Dose-Response Relationship, Drug; Erythrocytes; Female; Fibroblasts; Humans; Injections, Intravenous; Mice; Mice, Inbred ICR; Microbial Sensitivity Tests; Molecular Structure; Polyethylene Glycols; Rhizopus; Solubility; Structure-Activity Relationship; Water

Complement activation-related pseudoallergy (CARPA) is an acute adverse immune reaction caused by many nanomedicines. There is a regulatory need for a sensitive and standardizable in vivo predictive assay. While domestic pigs are a sensitive animal model, miniature pigs are favored in toxicological studies yet their utility as a CARPA model has not yet been explored. Herein, we used liposomal doxorubicin and amphotericin B (Doxil/Caelyx and AmBisome), Cremophor EL and zymosan as CARPA triggers to induce reactions in miniature and domestic pigs, and compared the hemodynamic, hematological, biochemical, and skin alterations. The changes observed after administration of the test agents were very similar in both pig strains, suggesting that miniature pigs are a sensitive, reproducible, and, hence, validatable animal model for CARPA regulatory testing.. With the advances in nanomedicine research, many new agents are now tested for use in clinical setting. Nonetheless, complement activation-related pseudoallergy (CARPA) is a well known phenomenon which can be caused by nanoparticles. In this study, the authors looked at and compared the use of domestic pigs versus miniature pigs as experimental animals for toxicological studies. Their findings confirmed the possible use of miniature pigs for regulatory testing.

Topics: Amphotericin B; Animals; Complement Activation; Disease Models, Animal; Doxorubicin; Drug Hypersensitivity; Glycerol; Humans; Liposomes; Nanomedicine; Nanoparticles; Polyethylene Glycols; Swine; Swine, Miniature; Zymosan

Scopulariopsisis an emerging opportunistic fungus characterized by its high resistance to antifungal therapies. We have developed a murine model of disseminated infection in immunosuppressed animals by intravenous inoculation ofScopulariopsis brevicaulisandScopulariopsis brumptii, the most clinically relevant species, in order to evaluate their virulence and their responses to conventional antifungal treatments. Survival and tissue burden studies showed thatS. brumptiiwas more virulent thanS. brevicaulis The three drugs tested, liposomal amphotericin B, posaconazole, and voriconazole, prolonged the survival of mice infected withS. brumptii, but none showed efficacy againstS. brevicaulis The different therapies were only able to modestly reduce the fungal burden of infected tissue; however, in general, despite the high serum levels reached, they showed poor efficacy in the treatment of the infection. Unfortunately, the most effective therapy forScopulariopsisinfections remains unresolved.

Topics: Amphotericin B; Animals; Antifungal Agents; Cyclophosphamide; Disease Models, Animal; Drug Resistance, Fungal; Humans; Immunocompromised Host; Male; Mice; Mycoses; Neutropenia; Scopulariopsis; Species Specificity; Survival Analysis; Triazoles; Virulence; Voriconazole

15-Deoxy-delta (12,14)-prostaglandin J2 (15d-PgJ2) is a potent bioactive lipid mediator, known to possess several roles in cell regulation and differentiation along with antimicrobial efficacy against different bacterial and viral infections. In the present study, we investigated the therapeutic efficacy and mechanism of action of 15d-PgJ2 in vitro in Leishmania donovani promastigotes and infected J774 macrophages, and in vivo in Balb/c mice/golden hamster model of experimental visceral leishmaniasis. 15d-PgJ2 effectively killed L. donovani promastigotes and amastigotes in vitro with IC50 of 104.6 and 80.09 nM, respectively. At 2 mg/kg (mice) and 4 mg/kg (hamster) doses, 15d-PgJ2 decreased >90 % spleen and liver parasite burden. It significantly reduced interleukin (IL)-10 and transforming growth factor (TGF)-β synthesis in infected macrophages and splenocytes. 15d-PgJ2 induced reactive oxygen species (ROS)-dependent apoptosis of promastigotes by triggering phosphatidyl serine externalization, mitochondrial membrane damage and inducing caspase-like activity. In vitro drug interaction studies revealed an indifference to the synergistic association of 15d-PgJ2 with Miltefosine and Amphotericin-B (Amp-B). Moreover, when combined with sub-curative doses of Miltefosine and Amphotericin-B, 15d-PgJ2 resulted in >95 % parasite removal. Our results suggested that 15d-PgJ2 induces mitochondria-dependent apoptosis of L. donovani and is a good therapeutic candidate for adjunct therapy against experimental visceral leishmaniasis.. 15d-PgJ2 effectively eliminated both promastigotes and amastigotes form of L. donovani. 15d-PgJ2 decreased parasite burden from infected mice and hamsters with reduced Th2 cytokines. 15d-PgJ2 induced ROS-mediated mitochondrial apoptosis of L. donovani promastigotes. 15d-PgJ2 is a good therapeutic candidate for adjunct therapy with Miltefosine and Amp-B.

Topics: Amphotericin B; Animals; Antiprotozoal Agents; Apoptosis; Cell Line; Cricetulus; Disease Models, Animal; Drug Administration Schedule; Female; Interleukin-10; Leishmania donovani; Leishmaniasis, Visceral; Life Cycle Stages; Liver; Macrophages; Male; Mice; Mice, Inbred BALB C; Mitochondria; Phosphorylcholine; Prostaglandin D2; Reactive Oxygen Species; Spleen; Transforming Growth Factor beta; Treatment Outcome

Candida kefyr is an emerging pathogen able to cause disseminated infection, especially in immunocompromised patients. Although guidelines for the treatment of invasive candidiasis have been published, no specific recommendations against C. kefyr are available. We determine the in vitro killing activity of amphotericin B (AMB), fluconazole (FLC) and caspofungin (CFG) as well as their efficacy in a murine model of systemic infection by two C. kefyr strains. Time-kill curves of AMB, FLC and CFG were determined in final volumes of 10 ml containing the assayed drugs ranged from 0.03 to 32 μg ml

Topics: Amphotericin B; Animals; Antifungal Agents; beta-Glucans; Candida; Candidiasis, Invasive; Caspofungin; Colony Count, Microbial; Disease Models, Animal; Echinocandins; Fluconazole; Kidney; Lipopeptides; Male; Mice; Microbial Sensitivity Tests; Microbial Viability; Proteoglycans; Survival Analysis; Treatment Outcome

The American Cutaneous Leishmaniasis (ACL) is an infectious disease that can be fatal. The first line of treatment is pentavalent antimonies. However, due to its potential to develop resistance, Amphotericin B (AmB) started to be used as an alternative medicine. Current treatments are limited, a fact that has led to a growing interesting in developing new therapies. This study aims to evaluate the therapeutic potential in vivo of an amphotericin B + oleic acid (OA) emulgel in the treatment of cutaneous leishmaniasis in an experimental model. Strains of Leishmania major MHOM/IL/80/Friendlin of Leishmania major were used. The animals were inoculated subcutaneously. After the development of leishmanial, nodular or ulcerative lesions, the animals were divided into three groups (control, Group A and Group B) and treated twice a day for twelve days. The weight of the animals was measured and the size of the lesions was observed. A histopathological analysis was performed with skin fragments of lesions and with the spleen of animals treated with different treatments (emulgel, AmB 3% emulgel and AmB 3% plus OA 5% emulgel). It was observed that when subjected to treatment with AmB 3% emulgel during the study period using both formulations, with enhancer and without enhancer, ulcerative lesions regress gradually or even complete cure. The quantification of the average number of parasites recovered from the inoculation site was made after the treatment in each group and the differences were considered significant. The treatment with AmB 3% and OA 5% emulgel had the best in vivo therapeutic response, showing good prospects for cutaneous leishmaniasis therapy as an alternative therapy.

Topics: Amphotericin B; Animals; Antiprotozoal Agents; Disease Models, Animal; Female; Gels; Hydrogen-Ion Concentration; Leishmania major; Leishmaniasis, Cutaneous; Male; Mice; Mice, Inbred BALB C; Oleic Acid; Spleen

We investigated efficacy of nitric oxide (NO) against Leishmania donovani. NO is a mediator of host response to infection, with direct parasiticidal activity in addition to its role in signalling to evoke innate macrophage responses. However, it is short-lived and volatile, and is therefore difficult to introduce into infected cells and maintain inracellular concentrations for meaningful periods of time. We incorporated diethylenetriamine NO adduct (DETA/NO), a prodrug, into poly(lactide-co-glycolide) particles of ∼200 nm, with or without amphotericin B (AMB). These particles sustained NO levels in mouse macrophage culture supernatants, generating an area under curve (AUC0.08-24h) of 591.2 ± 95.1 mM × h. Free DETA/NO resulted in NO peaking at 3 h and declining rapidly to yield an AUC of 462.5 ± 193.4. Particles containing AMB and DETA/NO were able to kill ∼98% of promastigotes and ∼76% of amastigotes in 12 h when tested in vitro. Promastigotes and amastigotes were killed less efficiently by particles containing a single drug- either DETA/NO (∼42%, 35%) or AMB (∼90%, 50%) alone, or by equivalent concentrations of drugs in solution. In a pre-clinical efficacy study of power >0.95 in the hamster model, DETA/NO particles were non-inferior to Fungizone® but not Ambisome®, resulting in significant (∼73%) reduction in spleen parasites in 7 days. Particles containing both DETA/NO and AMB were superior (∼93% reduction) to Ambisome®. We conclude that NO delivered to the cytosol of macrophages infected with Leishmania possesses intrinsic activity and adds significantly to the efficacy of AMB.

Topics: Amphotericin B; Animals; Antiprotozoal Agents; Cell Survival; Cricetinae; Disease Models, Animal; Drug Therapy, Combination; Leishmania donovani; Leishmaniasis, Visceral; Macrophages; Mice; Nanoparticles; Nitroso Compounds; Treatment Outcome

The aim of the present study was to evaluate the effects of delayed antifungal therapy on the outcome of invasive aspergillosis due to Aspergillus fumigatus in experimental models of infection.. A clinical isolate of A. fumigatus susceptible to amphotericin B (MIC 0.5 mg/L) and micafungin [minimum effective concentration (MEC) 0.03 mg/L] was used in all experiments. Two models of infection were investigated in immunosuppressed mice: disseminated infection and pulmonary infection. Twenty-four hours (early therapy) and 48 h (delayed therapy) post-infection, the mice were given vehicle, liposomal amphotericin B, micafungin or liposomal amphotericin B plus micafungin (combination). Drug efficacy was assessed by either survival or tissue burden experiments.. In disseminated infection, any drug regimen given early significantly prolonged survival. When therapy was delayed, only micafungin and the combination were effective. In pulmonary infection, although there was a trend towards a prolongation of survival of mice treated early with liposomal amphotericin B, only the combination was effective. Similarly, when therapy was delayed, only the combination was effective. In disseminated infection, any drug regimen given early was effective at reducing the cfu in kidney tissue. In pulmonary infection, only liposomal amphotericin B and the combination given early were effective at reducing the cfu in lung tissue. Conversely, when therapy was delayed, no regimen was effective at reducing the tissue burden, regardless of the type of infection.. Our data indicate that delayed initiation of antifungal therapy is deleterious in experimental models of invasive aspergillosis. A combination regimen seems to have some advantages over a single-drug approach when the therapy is started late.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillus fumigatus; Colony Count, Microbial; Disease Models, Animal; Drug Therapy, Combination; Echinocandins; Female; Invasive Pulmonary Aspergillosis; Lipopeptides; Lung; Micafungin; Mice; Microbial Sensitivity Tests; Survival Analysis; Time Factors; Treatment Outcome

The emergence of fluconazole-resistant Cryptococcus gattii is a global concern, since this azole is the main antifungal used worldwide to treat patients with cryptococcosis. Although pharmacokinetic (PK) and pharmacodynamic (PD) indices are useful predictive factors for therapeutic outcomes, there is a scarcity of data regarding PK/PD analysis of antifungals in cryptococcosis caused by resistant strains. In this study, PK/PD parameters were determined in a murine model of cryptococcosis caused by resistant C. gattii. We developed and validated a suitable liquid chromatography-electrospray ionization tandem mass spectrometry method for PK studies of fluconazole in the serum, lungs, and brain of uninfected mice. Mice were infected with susceptible or resistant C. gattii, and the effects of different doses of fluconazole on the pulmonary and central nervous system fungal burden were determined. The peak levels in the serum, lungs, and brain were achieved within 0.5h. The AUC/MIC index (area under the curve/minimum inhibitory concentration) was associated with the outcome of anti-cryptococcal therapy. Interestingly, the maximum concentration of fluconazole in the brain was lower than the MIC for both strains. In addition, the treatment of mice infected with the resistant strain was ineffective even when high doses of fluconazole were used or when amphotericin B was tested, confirming the cross-resistance between these drugs. Altogether, our novel data provide the correlation of PK/PD parameters with antifungal therapy during cryptococcosis caused by resistant C. gattii.

Topics: Amphotericin B; Animals; Antifungal Agents; Brain; Chromatography, Liquid; Colony Count, Microbial; Cryptococcosis; Cryptococcus gattii; Disease Models, Animal; Drug Resistance, Fungal; Fluconazole; Lung; Male; Mice, Inbred C57BL; Microbial Sensitivity Tests; Models, Biological; Spectrometry, Mass, Electrospray Ionization

To date, eight next‑generation urinary protein kidney safety biomarkers have been qualified to enable monitoring for subclinical drug‑induced kidney injury (DIKI) in rat preclinical studies; however, most DIKI biomarker studies have included only male rats. The objective of this study was to assess the utility of novel DIKI biomarkers, including but not limited to urinary total protein, albumin, cystatin C and osteopontin in female Sprague‑Dawley rats (8/group) that received repeated intravenous injections of amphotericin B (AmpB, 3 mg/kg/day) or vehicle for 10 consecutive days. Serial serum/urine samples were collected on study day (D)4, D8, and D11. Surviving animals were necropsied on D11. The AmpB‑induced kidney histopathology findings were characterized by cortical and medullary tubular alterations, interstitial inflammation, intratubular granular and inflammatory cell casts, acute pelvic inflammation and tubular mineralization. Significant elevations in urinary clusterin on D4, D8 and D11 (3.5 fold, 2.2 fold and 3.3 fold respectively) were observed (versus concurrent controls) following repeated injections of AmpB. In addition, significantly elevated (fold changes) in biomarkers, neutrophil gelatinase‑associated lipocalin (14.6 fold), albumin (13.5 fold), cystatin C (13.5 fold), total protein (3.5 fold), kidney injury molecule 1 (3.0 fold) and osteopontin (2.3 fold) were detected in urine as early as D4. These findings demonstrate the value of early elevations in nephron‑specific DIKI biomarkers for detecting subclinical AmpB nephrotoxicity in female Sprague‑Dawley rats. These findings are anticipated to provide the basis for inclusion of female rats on a case‑by‑case basis in preclinical toxicology studies designed to detect DIKI.

Topics: Albuminuria; Amphotericin B; Animals; Biomarkers; Disease Models, Animal; Female; Kidney Diseases; Nephrons; Predictive Value of Tests; Rats, Sprague-Dawley; Time Factors

Paracoccidioides brasiliensis and P. lutzii belong to a group of thermodimorphic fungi and cause paracoccidioidomycosis (PCM), which is a human systemic mycosis endemic in South and Central America. Patients with this mycosis are commonly treated with amphotericin B (AmB) and azoles. The study of fungal virulence and the efficacy and toxicity of antifungal drugs has been successfully performed in a Galleria mellonella infection model. In this work, G. mellonella larvae were infected with two Paracoccidioides spp. and the efficacy and toxicity of AmB and itraconazole were evaluated in this model for the first time. AmB and itraconazole treatments were effective in increasing larval survival and reducing the fungal burden. The fungicidal and fungistatic effects of AmB and itraconazole, respectively, were observed in the model. Furthermore, these effects were independent of changes in haemocyte number. G. mellonella can serve as a rapid model for the screening of new antifungal compounds against Paracoccidioides and can contribute to a reduction in experimental animal numbers in the study of PCM.

Topics: Amphotericin B; Animals; Antifungal Agents; Colony Count, Microbial; Disease Models, Animal; Drug Evaluation, Preclinical; Itraconazole; Larva; Lepidoptera; Paracoccidioides; Paracoccidioidomycosis; Survival Analysis; Treatment Outcome

Cryptococcosis is an opportunistic fungal infection responsible for high morbidity and mortality in immunocompromised patients. Combination of antifungal substances is a promising way to increase the percentage of successful treatment. Pedalitin (PED) is a natural substance obtained from Pterogyne nitens. The aim of this study was to verify the efficacy of PED alone and in combination with amphotericin B (AmB) in vitro and in vivo against Cryptococcus spp. In the in vitro assay, minimum inhibitory concentrations (MICs) of 0.125 mg/L for AmB and 3.9 mg/L for PED were found when the substances were tested alone, whilst in the combination treatment the active concentration of both decreased, with MICs of 0.03 mg/L for AmB and 1 mg/L for PED. In the survival assay, fungal burden study and histopathological assays it was possible to study the efficacy of the substances alone and in combination. The efficacy of combination therapy was considered better than monotherapy as evaluated in a Galleria mellonella model and a murine model. Thus, the combination of PED and AmB is an interesting alternative for anticryptococcal fungal treatment. Moreover, a correlation was observed between the invertebrate and murine models for this antifungal treatment combination.

Topics: Amphotericin B; Animals; Antifungal Agents; Colony Count, Microbial; Cryptococcosis; Cryptococcus neoformans; Disease Models, Animal; Drug Synergism; Flavones; Lepidoptera; Mice, Inbred BALB C; Microbial Sensitivity Tests; Survival Analysis; Treatment Outcome

PAF, a small antifungal protein from Penicillium chrysogenum, inhibits the growth of several pathogenic filamentous fungi, including members of the Aspergillus genus. PAF has been proven to have no toxic effects in vivo in mice by intranasal application. To test its efficacy against invasive pulmonary aspergillosis (IPA), experiments were carried out in mice suffering from IPA. Adult mice were immunosuppressed and then infected with Aspergillus fumigatus. After stable infection, the animals were inoculated with PAF intranasally at a concentration of 2.7 mg/kg twice per day. At this concentration-which is highly toxic in vitro to A. fumigatus-the mortality of the animals was slightly delayed but finally all animals died. Histological examinations revealed massive fungal infections in the lungs of both PAF-treated and untreated animal groups. Because intranasally administered PAF was unable to overcome IPA, modified and combined therapies were introduced. The intraperitoneal application of PAF in animals with IPA prolonged the survival of the animals only 1 day. Similar results were obtained with amphotericin B (AMB), with PAF and AMB being equally effective. Combined therapy with AMB and PAF-which are synergistic in vitro-was found to be more effective than either AMB or PAF treatment alone. As no toxic effects of PAF in mammals have been described thus far, and, moreover, there are so far no A. fumigatus strains with reported inherent or acquired PAF resistance, it is worth carrying out further studies to introduce PAF as a potential antifungal drug in human therapy.

Topics: Administration, Intranasal; Amphotericin B; Animals; Antifungal Agents; Aspergillus fumigatus; Disease Models, Animal; Drug Therapy, Combination; Fungal Proteins; Humans; Immunocompromised Host; Invasive Pulmonary Aspergillosis; Mice; Penicillium chrysogenum

From a fungicidal screen, we identified 2-(2-oxo-morpholin-3-yl)-acetamide derivatives as fungicidal agents against Candida species, additionally characterized by antifungal activity against Aspergillus species. However, development of this series was hampered by low plasmatic stability. Introduction of a gem-dimethyl on the 6-position of the morpholin-2-one core led to considerable improvement in plasmatic stability while maintaining in vitro antifungal activity. Further optimization of the series resulted in the discovery of N-(biphenyl-3-ylmethyl)-2-(4-ethyl-6,6-dimethyl-2-oxomorpholin-3-yl)acetamide (87), which, in addition to fungicidal activity against Candida species, shows promising and broad antifungal in vitro activity against various fungi species, such as molds and dermatophytes. In vivo efficacy was also demonstrated in a murine model of systemic Candida albicans infection with a significant fungal load reduction in kidneys.

Topics: Acetamides; Animals; Antifungal Agents; Candida; Candidiasis; Disease Models, Animal; Dose-Response Relationship, Drug; Male; Mice; Mice, Inbred BALB C; Microbial Sensitivity Tests; Molecular Structure; Morpholines; Species Specificity; Structure-Activity Relationship; Substrate Specificity

To evaluate the antifungal activity of amphotericin B (AmB) in a mouse model of systemic candidiasis following administration of a novel oral AmB formulation (iCo-010) that has been pre-exposed to tropical temperatures.. Amphotericin B (AmB) was prepared as a 5 mg/mL dispersion in a mixture of Peceol, Gelucire 44/14 and VitE-TPGS 2,3 (iCo-010). The formulation was protected from light and incubated in a sealed container at 43 °C for 60 days. Mice infected with Candida albicans were treated with either iCo-010 formulation pre-incubated at 43 °C for 60 days or freshly prepared iCo-010 formulation at doses of 5, 10 and 20 mg/kg once daily for five consecutive days. Single intravenous 5 mg/kg dose of AmBisome® was used as a positive control group. Seven days following the last dose, the kidney, liver, spleen, lung, heart and brain were removed and the number of colony forming units (CFUs) was determined as a measure of tissue fungal load. In addition, the concentration of AmB within each tissue was determined using high performance liquid chromatography (HPLC).. There were no significant differences in the reduction of CFUs and the concentration of AmB recovered in all organs at all iCo-010 doses tested between the freshly prepared iCo-010 formulation compared to the formulation that was incubated at 43 °C for 60 days.. A novel oral AmB formulation, iCo-010, incubated at 43 °C for 60 days to simulate the exposure of the formulation to tropical temperatures remained highly effective against murine systemic candidiasis.

Topics: Administration, Oral; Amphotericin B; Animals; Antifungal Agents; Candida albicans; Candidiasis; Chromatography, High Pressure Liquid; Colony Count, Microbial; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Stability; Drug Storage; Excipients; Female; Mice; Mice, Inbred BALB C; Temperature; Tissue Distribution; Tropical Climate

Sporothrix brasiliensis is a highly virulent member of the S. schenckii complex, which is responsible for the emergence of the epidemic sporotrichosis in southeastern Brazil over the last two decades. There are no in vivo studies on the sensitivity of S. brasiliensis to the therapeutic regimens used to treat sporotrichosis. Here, we evaluated the efficacy and safety of antifungal treatments against S. brasiliensis using a murine model of disseminated sporotrichosis. In vitro, S. brasiliensis yeasts were sensitive to low concentrations of amphotericin B-deoxycholate (AMB-d) and itraconazole (ITZ), the latter having greater selectivity toward the fungus. The following treatment regimens were tested in vivo: intravenous AMB-d for 7 days post-infection (p.i.), oral ITZ for up to 30 days p.i., and AMB-d followed by ITZ (AMB-d/ITZ). AMB-d and AMB-d/ITZ led to 100% survival of infected mice at the end of the 45-day experimental period. Although all treatments extended mice survival, only AMB-d and AMB-d/ITZ significantly reduced fungal load in all organs, but AMB-d/ITZ led to a more consistent decrease in overall fungal burden. No treatment increased the levels of serum toxicity biomarkers. Taken together, our results indicate that AMB-d/ITZ is the best therapeutic option for controlling disseminated sporotrichosis caused by S. brasiliensis.

Topics: Amphotericin B; Animals; Antifungal Agents; Colony Count, Microbial; Disease Models, Animal; Drug Therapy; Itraconazole; Male; Mice, Inbred BALB C; Sporothrix; Sporotrichosis; Survival Analysis; Treatment Outcome

The present study developed Galleria mellonella and murine infection models for the study of Trichosporon infections. The utility of the developed animal models was demonstrated through the assessment of virulence and antifungal efficacy for 7 clinical isolates of Trichosporon asahii, T. asteroides and T. inkin. The susceptibility of the Trichosporon isolates to several common antifungal drugs was tested in vitro using the broth microdilution and the E-test methods. The E-test method depicted a lower minimal inhibitory concentration (MIC) for amphotericin and a slightly higher MIC for caspofungin, while MICs observed for the azoles were different but comparable between both methods. All three Trichosporon species established infection in both the G. mellonella and immunosuppressed murine models. Species and strain dependent differences were observed in both the G. mellonella and murine models. T. asahii was demonstrated to be more virulent than the other 2 species in both animal hosts. Significant differences in virulence were observed between strains for T. asteroides in the murine model. In both animal models, fluconazole and voriconazole were able to improve the survival of the animals compared to the untreated control groups infected with any of the 3 Trichosporon species. In G. mellonella, amphotericin was not able to reduce mortality in any of the 3 species. In contrast, amphotericin was able to reduce murine mortality in the T. asahii or T. inkin models, respectively. Hence, the developed animal infection models can be directly applicable to the future deeper investigation of the molecular determinants of Trichosporon virulence and antifungal resistance.

Topics: Amphotericin B; Animals; Antifungal Agents; Caspofungin; Disease Models, Animal; Drug Resistance, Fungal; Echinocandins; Fluconazole; Immunocompromised Host; Kidney; Larva; Lipopeptides; Mice; Microbial Sensitivity Tests; Moths; Trichosporon; Trichosporonosis; Voriconazole

Acute renal injury may occur after amphotericin B (AmB) administration. The hypothesized injury mechanism is renal vasoconstriction and direct toxic damage. Hyperbaric oxygen therapy (HBO) is indicated for treatment of many ischemic events but not for acute renal failure (ARF). The aim of this study was to investigate the role of HBO therapy in AmB induced ARF.. ARF was induced in 41 Sprague-Dawley rats by a single dose of 75 mg/kg AmB. The rats were randomly divided into two groups; one group was treated with daily HBO for 3 consecutive days. The control group received no HBO treatment. Parameters of renal function were taken on the 5th day after AmB administration.. Forty-one rats were treated with AmB, 21 received HBO and 20 served as controls. Body weight loss following the administration of AmB was 13.5+14.7% in the HBO treated rats, as opposed to 24.6+5% in the control group (P=0.004). Serum creatinine and urea were 0.49+0.13 mg/dL and 200.63+87.82 mg/dL in the treatment group and 0.70+0.22 mg/dL and 368.01+169.35 mg/dL, respectively in the control (P=0.001).. In this model of AmB-induced ARF, HBO treatment alleviated renal injury as reflected by changes in serum creatinine and urea levels.

Topics: Acute Kidney Injury; Amphotericin B; Animals; Anti-Bacterial Agents; Biomarkers; Creatinine; Disease Models, Animal; Hyperbaric Oxygenation; Kidney Function Tests; Random Allocation; Rats; Rats, Sprague-Dawley; Urea; Weight Loss

Despite recent advances in the treatment of some forms of leishmaniasis, the available drugs are still far from ideal due to inefficacy, parasite resistance, toxicity and cost. The wide-spectrum antimicrobial activity of 2-nitrovinylfuran compounds has been described, as has their activity against Trichomonas vaginalis and other protozoa. Thus, the aim of this study was to test the antileishmanial activities of six 2-nitrovinylfurans in vitro and in a murine model of leishmaniasis. Minimum parasiticide concentration (MPC) and 50% inhibitory concentration (IC50) values for these compounds against the promastigotes of Leishmania amazonensis, Leishmania infantum and Leishmania braziliensis were determined, as were the efficacies of two selected compounds in an experimental model of cutaneous leishmaniasis (CL) caused by L. amazonensis in BALB/c mice. All of the compounds were active against the promastigotes of the three Leishmania species tested. IC50 and MPC values were in the ranges of 0.8-4.7 µM and 1.7-32 µM, respectively. The compounds 2-bromo-5-(2-bromo-2-nitrovinyl)-furan (furvina) and 2-bromo-5-(2-methyl-2-nitrovinyl)-furan (UC245) also reduced lesion growth in vivo at a magnitude comparable to or higher than that achieved by amphotericin B treatment. The results demonstrate the potential of this class of compounds as antileishmanial agents and support the clinical testing of Dermofural(r) (a furvina-containing antifungal ointment) for the treatment of CL.

Topics: Amphotericin B; Animals; Antiprotozoal Agents; Cell Proliferation; Clinical Trials as Topic; Disease Models, Animal; Female; Furans; Humans; In Vitro Techniques; Inhibitory Concentration 50; KB Cells; Leishmania; Leishmaniasis, Cutaneous; Mice, Inbred BALB C; Neglected Diseases; Time Factors; Vinyl Compounds

Amphotericin B (Ampho B) isa fungicidal drug that causes cell wall injury. Pharmacological ascorbate induces the extracellular prooxidants, which might enter the Ampho B-induced cell wall porosity and act synergistically.W e tested low-dose Ampho B with a short course of pharmacological ascorbate using a mouse model of sepsis preconditioned with an injection of Candida albicans 6 h prior to cecal ligation and puncture (CLP). In this model, candidemia reappeared as early as 6 h after CLP with a predictably high mortality rate. This characteristic mimics sepsis in the phase of immunosuppression inpatients. Using the model, at 12- and 18-h post-CLP, we administered isotonic (pH neutralized) pharmacological ascorbate intravenously with low-dose Ampho B or sodium deoxycholate, vehicle-controlled, administered IP. The survival rate of low-dose Ampho B plus ascorbate was 53%, compared with < 11% for low-dose Ampho B or high-dose Ampho B alone. In addition, a beneficial effect was demonstrated in terms of kidney damage,liver injury, spleen histopathology, and serum markers at 24 h after CLP. Kidney injury was less severe in low-dose Ampho B plus ascorbate combination therapy due to less severe sepsis. Moreover, ascorbate enhanced the effectiveness of phagocytosis against C. albicans in human phagocytic cells. Taken together, the data indicate that the new mouse model simulates sepsis-induced immunosuppression and that the combination of pharmacological ascorbate with an antifungal drug is a potentially effective treatment that may reduce nephrotoxicity, and perhaps also increase fungicidal activity in patients with systemic candidiasis caused by Candida albicans.

Topics: Amphotericin B; Animals; Ascorbic Acid; Candidemia; Disease Models, Animal; Drug Combinations; Kidney; Liver; Male; Mice, Inbred BALB C; Sepsis; Spleen

The aim of this study was to investigate if the alternative in vivo model Galleria mellonella can be used (i) to determine differences in pathogenicity of amphotericin B (AMB) resistant and susceptible A. terreus isolates, (ii) to evaluate AMB efficacy in vivo (iii) and to correlate outcome to in vitro susceptibility data. Larvae were infected with 2 A. terreus AMB resistant (ATR) and 3 AMB susceptible (ATS) isolates and survival rates were correlated to physiological attributes and killing ability of larval haemocytes. Additionally, infected larvae were treated with different concentrations of L-AMB. Haemocyte density were ascertained to evaluate the influence of L-AMB on the larval immune cells. Larvae were sensitive to A. terreus infection in an inoculum-size and temperature dependent manner. In vitro susceptibility to L-AMB correlated with in vivo outcome of antifungal treatment, defining an AMB susceptible strain cluster of A. terreus. Susceptibility to L-AMB increased virulence potential in the larval model, but this increase was also in accordance with faster growth and less damage caused by larval haemocytes. L-AMB treatment primed the larval immune response by increasing haemocyte density. G. mellonella provides a convenient model for the in vivo screening of A. terreus virulence and treatment options, contributing to the generation of a hypothesis that can be further tested in refined experiments in mammalian models.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillus; Disease Models, Animal; Drug Resistance, Fungal; Hemocytes; Larva; Lepidoptera; Survival Analysis; Treatment Outcome; Virulence

Topics: Amphotericin B; Animals; Antifungal Agents; Disease Models, Animal; Female; Itraconazole; Madurella; Mice, Inbred BALB C; Mycetoma

To compare the effects of voriconazole (VCZ) and liposomal amphotericin B (Amp-B) in an experimental model of Aspergillus fumigatus endophthalmitis.. Thirty guinea pigs received an intravitreal injection of A. fumigatus to induce endophthalmitis. The animals were randomly divided into three groups, including control (0.02 mL balanced salt solution intravitreal injection) and experimental (20 μg VCZ/0.02 mL or 20 μg liposomal Amp-B/0.02 mL intravitreal injection) groups. Corneal opacity, aqueous flare, and vitreous opacity were graded, and electroretinographic examinations were performed at multiple time points. At 28 days post treatment, histopathology was performed to examine the retinal architecture.. The inflammation in the VCZ and liposomal Amp-B groups was milder than that in the control group. Corneal opacity, aqueous flare, and vitreous opacity scores, as well as electroretinographic recording, showed significantly less inflammation in the VCZ group compared with the liposomal Amp-B group during the early and middle stages of endophthalmitis (P < 0.05). Normal histologic structure of the retina was observed in eyes treated with VCZ and liposomal Amp-B.. Both intravitreal VCZ and liposomal Amp-B were effective treatments for A. fumigatus-induced endophthalmitis in guinea pigs. Voriconazole was superior to liposomal Amp-B at doses similar to the initial therapy for acute infections. Further experimental and clinical studies are required to confirm the efficacy of these two antifungal drugs. Chinese Abstract.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Disease Models, Animal; Electroretinography; Endophthalmitis; Eye Infections, Fungal; Guinea Pigs; Intravitreal Injections; Voriconazole

To investigate the ocular toxicity and pharmacokinetics of intrastromal injection of amphotericin B (AmB) in a rabbit model.. Forty albino rabbits were randomly divided into five groups (eight per group). The rabbits were anesthetized before they received the medication. Intrastromal injection of 0.1 ml balanced salt solution containing 0, 5, 10, 20 or 30 μg of AmB was performed on eyes of each group five times (once per four days), respectively. The presence of possible corneal clouding, epithelial erosion and corneal neovascularization was monitored with a slit-lamp biomicroscope. Corneal ultrasonic pachymetry was used to detect the corneal thickness of intrastromal-injected eyes. Thirty days after the last injection, the corneal transparency as well as the number and ultrastucture of corneal endothelial cells were examined. The concentrations of the AmB in the cornea and aqueous humor were evaluated at 30 min, 6 h and at 1, 3 and 7 days after the intrastromal injection of 10 µg AmB.. Intrastromal injection of AmB at concentrations of 5 and 10 μg per 0.1 ml did not induce obvious toxicity to the cornea when compared with the controls. However, when the concentration of AmB increased to 20 μg per 0.1 ml or more, corneal edema, corneal epithelial erosion and severe neovascularization appeared. A single intrastromal injection of 10 μg AmB achieved an effective drug level in corneas which was maintained for up to 7 days.. Intrastromal injection of AmB at a concentration of less than 10 μg per 0.1 ml is safe to the rabbit corneas. Intrastromal injection of AmB may be an adjunctive treatment for deep recalcitrant fungal keratitis.

Topics: Amphotericin B; Animals; Anti-Bacterial Agents; Antifungal Agents; Aqueous Humor; Corneal Neovascularization; Corneal Stroma; Disease Models, Animal; Eye Infections, Fungal; Injections; Keratitis; Rabbits

The in vitro activities of fluconazole (FLC), amphotericin B (AmB) and caspofungin (CSP) were evaluated against three isolates of Candida lusitaniae using time-kill curves. AmB showed in vitro fungicidal activity, whilst FLC and CSP exerted mainly strain-dependent fungistatic activity. The in vivo efficacies of the three drugs were evaluated in a murine model of disseminated infection. The doses administered were FLC 50 mg/kg/day, AmB 0.8 mg/kg/day and CSP 5 mg/kg/day. All three drugs were able to reduce the fungal burden in the kidneys of infected mice, with AmB showing the highest efficacy, followed by CSP. At least in this model, FLC, AmB and CSP are good candidates for treating invasive infections by C. lusitaniae.

Topics: Amphotericin B; Animals; Antifungal Agents; Candida; Candidiasis; Caspofungin; Colony Count, Microbial; Disease Models, Animal; Echinocandins; Fluconazole; Kidney; Lipopeptides; Male; Mice; Microbial Sensitivity Tests; Treatment Outcome

Invasive pulmonary mucormycosis is a life-threatening fungal infection encountered in immunocompromised patients. An intravenous high-dose lipid formulation of amphotericin B, such as liposomal amphotericin B (L-AMB), is the recommended treatment. The efficacy of inhaled L-AMB against mucormycosis has not been evaluated. We evaluated the efficacy of inhaled aerosolized L-AMB in murine invasive pulmonary mucormycosis. ICR female mice were immunosuppressed with cortisone acetate and cyclophosphamide and challenged on day 0 with 1 × 10⁶ conidia of Rhizopus oryzae (TIMM 1327) intratracheally. Infected mice were assigned to one of the following 3 treatment groups: (i) control, (ii) treatment only (aerosolized L-AMB from day 1-5 after challenge), and (iii) prophylaxis followed by treatment (aerosolized L-AMB from day -2 to 5 before and after challenge). Survival was monitored until 12 days after challenge. For fungal-burden and histopathological examination, mice were sacrificed 4 h after treatment on day 3. Numbers of colony-forming units per lung were calculated. To study the distribution of AMB after inhalation of L-AMB, immunohistochemical studies using AMB antibody were performed. Aerosolized L-AMB significantly improved survival rate and decreased fungal burden compared with control group, and histopathology findings were superior to those of control group. However, no significant differences were detected between the treatment-only and prophylaxis followed by treatment groups. Immunohistochemical analysis showed that L-AMB was promptly distributed in lung tissue after inhalation therapy. Aerosolized L-AMB showed modest efficacy against R. oryzae infection in mice treated after fungal challenge. Prophylaxis with aerosolized L-AMB was not effective in this animal model.

Topics: Administration, Inhalation; Aerosols; Amphotericin B; Animals; Antibiotic Prophylaxis; Bronchoalveolar Lavage Fluid; Disease Models, Animal; Female; Lung Diseases, Fungal; Mice; Mice, Inbred ICR; Mucormycosis; Survival Analysis; Treatment Outcome

Cryptococcal meningoencephalitis is an urgent global health problem. Induction regimens using 14 days of amphotericin B deoxycholate (dAmB) are considered the standard of care but may not be suitable for resource-poor settings. We investigated the efficacy of conventional and abbreviated regimens of dAmB for cryptococcal meningoencephalitis in both murine and rabbit models of cryptococcal meningoencephalitis. We examined the extent to which immunological effectors contribute to the antifungal effect. We bridged the results to humans as a first critical step to define regimens suitable for further study in clinical trials. There were significant differences in the murine plasma-versus-cerebrum dAmB concentration-time profiles. dAmB was detectable in the cerebrum throughout the experimental period, even following the administration of only three doses of 3 mg/kg. dAmB induced a fungistatic effect in the cerebrum with a 2- to 3-log10 CFU/g reduction compared with controls. The effect of 3 days of therapy was the same as that of daily therapy for 14 days. There was no evidence of increased numbers of CD3(+) CD4(+) or CD3(+) CD8(+) cells in treated mice to account for the persistent antifungal effect of an abbreviated regimen. The administration of dAmB at 1 mg/kg/day for 3 days was the same as daily therapy in rabbits. The bridging studies suggested that a human regimen of 0.7 mg/kg/day for 3 days resulted in nearly maximal antifungal activity in both the cerebrum and cerebrospinal fluid. An abbreviated regimen (3 days of therapy) of dAmB appears to be just as effective as conventional induction therapy for cryptococcal meningoencephalitis.. Cryptococcal meningitis is a significant and neglected infection that is associated with excessive morbidity and mortality. In well-resourced health care settings, induction therapy with at least 2 weeks of amphotericin B deoxycholate (dAmB) is advocated. Multiple clinical studies suggest that dAmB is the drug of choice for cryptococcal meningitis. In many parts of the world where the burden of cryptococcal meningitis is highest, it is infeasible to administer dAmB for prolonged periods. This paper provides the experimental basis for the efficacy of abbreviated regimens of dAmB for cryptococcal meningitis. The concept was explored in two well-validated laboratory animal models of cryptococcal meningitis, and the results were bridged to humans by using a range of mathematical modeling techniques. A 3-day regimen is as effective as the standard 14-day course. An abbreviated regimen is significantly more feasible and may enable better antifungal therapy to be administered to many patients with this frequently lethal disease.

Topics: Amphotericin B; Animals; Antifungal Agents; Cerebrospinal Fluid; Cerebrum; Deoxycholic Acid; Disease Models, Animal; Drug Combinations; Male; Meningitis, Cryptococcal; Mice; Plasma; Rabbits

Leishmaniasis chemotherapy remains very challenging. The high cost of active drugs, along with the severity of their side effects and the increasing failure rate of the current therapeutic schemes, calls for the discovery of new active drugs and schemes of treatment. The use of combination therapy has gained much attention in recent years as a possible strategy for overcoming the various shortcomings in the present arsenal. We recently described the effectiveness of tamoxifen in murine models of leishmaniasis, and here, we investigated the interactions between tamoxifen and amphotericin B, one of the most potent drugs used in leishmaniasis treatment. The in vitro interactions were indifferent for the association of tamoxifen and amphotericin B. The association was also assayed in vivo in Leishmania amazonensis-infected BALB/c mice and was found to yield at least additive effects at low doses of both drugs.

Topics: Amphotericin B; Animals; Antiprotozoal Agents; Disease Models, Animal; Female; Leishmaniasis, Cutaneous; Mice; Mice, Inbred BALB C; Tamoxifen

Invasive pulmonary aspergillosis (IPA) is a life-threatening disease of immunocompromised patients that requires aggressive therapy. Detection of the disease and monitoring of the therapeutic response during IPA are complex, and current molecular diagnostics are not suitably robust. Here, we explored proteomic profiles of bronchoalveolar lavage fluid (BALF) specimens from a persistently neutropenic rabbit model of IPA. Three experimental arms, uninfected control animals, infected untreated animals, and animals infected and treated with ravuconazole/amphotericin B, were studied. Total proteins were evaluated by two-dimensional (2D) gel electrophoresis, followed by matrix-assisted laser desorption ionization-time of flight/time of flight (MALDI-TOF/TOF) mass spectrometry (MS) and quantified by enzyme-linked immunosorbent assay (ELISA). Host-derived proteins haptoglobin (Hp), C-reactive protein (CRP), and annexin A1 (Anx A1) were prominently found in BALF during the IPA infection and showed significant changes in response to antifungal therapy (P < 0.0001). In serum, differences in Hp (P = 0.0001) between infected and treated rabbits were observed. Preliminary in vitro studies revealed that Aspergillus fumigatus-secreted proteases may contribute to the cleavage of Anx A1 during IPA. In summary, host protein biomarkers Hp, CRP, and Anx A1 may have value in monitoring therapeutic response to antifungal agents in IPA patients with confirmed disease.

Topics: Amphotericin B; Animals; Annexin A1; Antifungal Agents; Aspergillus fumigatus; Biomarkers; Bronchoalveolar Lavage Fluid; C-Reactive Protein; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Humans; Invasive Pulmonary Aspergillosis; Neutropenia; Proteomics; Rabbits; Thiazoles; Triazoles

We have evaluated the efficacy of amphotericin B, posaconazole, and voriconazole in immunosuppressed murine models of disseminated infection by Curvularia spicifera and Curvularia hawaiiensis. The 3 antifungals improved survival of mice in comparison to controls; however, only the 2 azoles were able to reduce significantly the fungal load.

Topics: Amphotericin B; Animals; Antifungal Agents; Ascomycota; Disease Models, Animal; Immunocompromised Host; Male; Mice; Mycoses; Treatment Outcome; Triazoles; Voriconazole

To evaluate the efficacy of the combination of allicin and amphotericin deoxycholate (AmB) in the chemotherapy of Leishmania infantum infection with the final aim of reducing the dose of AmB in the chemotherapy of visceral leishmaniasis.. Hamsters were intraperitoneally (ip) infected with L. infantum (10(7) stationary phase promastigotes). On day 45 post-infection animals were treated ip with AmB (1 or 5 mg/kg/day), allicin (5 mg/kg/day) or a combination of AmB (1 mg/kg/day) + allicin (5 mg/kg/day) for 5 days. Animals were clinically and biopathologically monitored and the antibody response (IgG, IgG1, IgG2) was determined. Parasite burdens were estimated by limiting dilution and AmB biodistribution was determined by HPLC in plasma, kidney, spleen and liver.. No clinical signs or liver and kidney alterations were observed. AmB (1 mg/kg/day) did not clear the Leishmania infection and no parasites were detected in two animals treated with 5 mg/kg/day allicin. Combination therapy (5 mg/kg allicin + 1 mg/kg AmB) reduced the L. infantum burden by >95%. Antileishmanial activity of the combination was comparable (P < 0.05) to the standard AmB treatment (5 mg/kg).. Allicin alone (5 mg/kg/day for 5 days) significantly reduced the Leishmania burden in spleen and liver of infected hamsters. Co-administration of allicin (5 mg/kg/day for 5 days) and AmB (1 mg/kg/day for 5 days) showed a partial additive effect on the reduction of leishmanial burden in both target organs.

Topics: Amphotericin B; Animal Structures; Animals; Antiprotozoal Agents; Chromatography, High Pressure Liquid; Cricetinae; Disease Models, Animal; Disulfides; Drug Therapy, Combination; Female; Leishmania infantum; Leishmaniasis, Visceral; Parasite Load; Plasma; Sulfinic Acids; Treatment Outcome

We used two established neutropenic murine models of pulmonary aspergillosis and mucormycosis to explore the association between the posaconazole area under the concentration-time curve (AUC)-to-MIC ratio (AUC/MIC) and treatment outcome. Posaconazole serum pharmacokinetics were verified in infected mice to ensure that the studied doses reflected human exposures with the oral suspension, delayed-release tablet, and intravenous formulations of posaconazole. Sinopulmonary infections were then induced in groups of neutropenic mice with Aspergillus fumigatus strain 293 (posaconazole MIC, 0.5 mg/liter) or Rhizopus oryzae strain 969 (posaconazole MIC, 2 mg/liter) and treated with escalating daily dosages of oral posaconazole, which was designed to achieve AUCs ranging from 1.10 to 392 mg · h/liter. After 5 days of treatment, lung fungal burden was analyzed by quantitative real-time PCR. The relationships of the total drug AUC/MIC and the treatment response were similar in both models, with 90% effective concentrations (EC90s) corresponding to an AUC/MIC threshold of 76 (95% confidence interval [CI], 46 to 102) for strain 293 versus 87 (95% CI, 66 to 101) for strain 969. Using a provisional AUC/MIC target of >100, these exposures correlated with minimum serum posaconazole concentrations (Cmins) of 1.25 mg/liter for strain 293 and 4.0 mg/liter for strain 969. The addition of deferasirox, but not liposomal amphotericin or caspofungin, improved the activity of a suboptimal posaconazole regimen (AUC/MIC, 33) in animals with pulmonary mucormycosis. However, no combination was as effective as the high-dose posaconazole monotherapy regimen (AUC/MIC, 184). Our analysis suggests that posaconazole pharmacodynamics are similar for A. fumigatus and R. oryzae when indexed to pathogen MICs.

Topics: Amphotericin B; Animals; Antifungal Agents; Area Under Curve; Aspergillosis; Aspergillus fumigatus; Benzoates; Caspofungin; Deferasirox; Disease Models, Animal; Drug Therapy, Combination; Echinocandins; Female; Invasive Pulmonary Aspergillosis; Lipopeptides; Lung; Mice; Mice, Inbred BALB C; Microbial Sensitivity Tests; Mucormycosis; Neutropenia; Rhizopus; Treatment Outcome; Triazoles

Immune cells express the vitamin D receptor and vitamin D metabolizing enzymes. Favorable vitamin D effects have been indicated in tuberculosis. Vitamin D deficiency increases T helper (Th) 2 responses to Aspergillus, and it suppresses Th2 responses in cystic fibrosis-allergic bronchopulmonary aspergillosis. Can vitamin D modulate the proinflammatory effects of amphotericin B (AmB) therapy in aspergillosis? Groups of mice were infected intravenously (IV) with 3-8 × 10(6) Aspergillus fumigatus conidia. In six experiments, doses of 0.08, 2, or 4 μg/kg calcitriol (active form of vitamin D) were given intraperitoneally +/- AmB-deoxycholate (AmBd) at 0.4, 0.8, 1.2, 1.8, 3.3, or 4.5 mg/kg or 0.8 or 1.2 mg/kg IV. Calcitriol doses were selected to range from doses used in humans to those just below doses shown to decalcify murine bones. In most experiments, doses of calcitriol and AmBd (or control diluents) were given five times, on alternate days, to minimize drug-drug interactions. Calcitriol treatment began on the day of challenge, and survival assessed for 10 days. In no experiments did calcitriol alone significantly worsen or enhance survival or affect residual infection in survivors. Calcitriol also did not affect the efficacy of AmBd. In a representative experiment, AmBd at 0.8 or 1.2 mg/kg IV alone +/- calcitriol at 2 μg/kg enhanced survival (P ≤ 0.01). However, the AmBd regimens with calcitriol were not different than those without, and calcitriol alone was identical to controls. In disseminated invasive aspergillosis, calcitriol did not affect outcome nor influence antifungal efficacy.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Calcitriol; Colony Count, Microbial; Deoxycholic Acid; Disease Models, Animal; Drug Combinations; Female; Mice; Survival Analysis

Penicillium marneffei, one of the most important thermal dimorphic fungi, is a severe threat to the life of immunocompromised patients. However, the pathogenic mechanisms of P. marneffei remain largely unknown. In this work, we developed a model host by using nematode Caenorhabditis elegans to investigate the virulence of P. marneffei. Using two P. marneffei clinical isolate strains 570 and 486, we revealed that in both liquid and solid media, the ingestion of live P. marneffei was lethal to C. elegans (P<0.001). Meanwhile, our results showed that the strain 570, which can produce red pigment, had stronger pathogenicity in C. elegans than the strain 486, which can't produce red pigment (P<0.001). Microscopy showed the formation of red pigment and hyphae within C. elegans after incubation with P. marneffei for 4 h, which are supposed to be two contributors in nematodes killing. In addition, we used C. elegans as an in vivo model to evaluate different antifungal agents against P. marneffei, and found that antifungal agents including amphotericin B, terbinafine, fluconazole, itraconazole and voriconazole successfully prolonged the survival of nematodesinfected by P. marneffei. Overall, this alternative model host can provide us an easy tool to study the virulence of P. marneffei and screen antifungal agents.

Topics: Amphotericin B; Animals; Antifungal Agents; Caenorhabditis elegans; Disease Models, Animal; Fluconazole; Host-Pathogen Interactions; Hyphae; Itraconazole; Mycoses; Naphthalenes; Penicillium; Pigments, Biological; Survival Analysis; Terbinafine; Voriconazole

The efficacy of polyene macrolides to treat experimental Trichosporon bloodstream infection was evaluated by histopathological examination and viable cell counts in the kidneys of infected mice. Viable cell counts on the 5th day after infection confirmed that liposomal amphotericin B (L-AMB) is a more effective treatment than fluconazole (FLC) for mice infected with an azole-resistant strain of Trichosporon. Histological examination revealed that the administration of L-AMB induced a transformation from acute purulent inflammation caused by both azole-susceptible and -resistant strain infections to a chronic and subsiding form, whereas FLC failed to convert the acute inflammation induced by the azole-resistant strain to a subsiding form. Our results demonstrate that polyene macrolides can be used as an alternative therapy for infection of azole-resistant strains of Trichosporon and that histopathological evaluation is useful for elucidating the pathophysiology of an experimental Trichosporon infection.

Topics: Amphotericin B; Animals; Antifungal Agents; Colony Count, Microbial; Disease Models, Animal; Fluconazole; Fungemia; Histocytochemistry; Kidney; Macrolides; Male; Mice; Microbial Viability; Polyenes; Trichosporon; Trichosporonosis

Mucormycosis is a life-threatening fungal infection almost uniformly affecting diabetics in ketoacidosis or other forms of acidosis and/or immunocompromised patients. Inhalation of Mucorales spores provides the most common natural route of entry into the host. In this study, we developed an intratracheal instillation model of pulmonary mucormycosis that hematogenously disseminates into other organs using diabetic ketoacidotic (DKA) or cyclophosphamide-cortisone acetate-treated mice. Various degrees of lethality were achieved for the DKA or cyclophosphamide-cortisone acetate-treated mice when infected with different clinical isolates of Mucorales. In both DKA and cyclophosphamide-cortisone acetate models, liposomal amphotericin B (LAmB) or posaconazole (POS) treatments were effective in improving survival, reducing lungs and brain fungal burdens, and histologically resolving the infection compared with placebo. These models can be used to study mechanisms of infection, develop immunotherapeutic strategies, and evaluate drug efficacies against life-threatening Mucorales infections.

Topics: Amphotericin B; Animals; Antifungal Agents; Cortisone; Cyclophosphamide; Diabetic Ketoacidosis; Disease Models, Animal; Male; Mice; Mice, Inbred ICR; Mice, Inbred NOD; Microbial Sensitivity Tests; Mucorales; Mucormycosis; Triazoles

Current therapy for leishmaniasis is limited and unsatisfactory. Amphotericin B, a second-line treatment is gradually replacing antimonials, the first-line treatment and is used as the preferred treatments in some regions. Though, presently it is the only drug with highest cure rate, its use is severely restricted by its acute toxicity. In the present study novel lipid-amphotericin B formulations with lower toxicity than the parent drug were evaluated for the treatment of visceral leishmaniasis (VL) in a mouse model.. The toxicity and therapeutic efficacy of a new amphiphilic formulation of amphotericin B (Kalsome10) was compared to that of amphotericin B deoxycholate (Fungizone) in a mouse model of VL using quantitative real-time PCR (qRT-PCR).. The toxicity of amphotericin B was significantly less with liposomal formulation as compared to the deoxycholate form, evidenced by reduced nephrotoxicity and higher tolerated dose in BALB/c mice. The therapeutic efficacy was evaluated by quantitative real time (RT) PCR using primers highly specific for the ITS region of Leishmania donovani. There was reduction in parasite load by 2 log unit after 7 days of treatment and finally resulting in complete clearance of parasite from infected mice after 30 days of treatment with Kalsome10.. This new formulation showed a favourable safety profile and better efficacy when compared to conventional amphotericin B. If production cost is kept low, it may prove to be a feasible alternative to conventional amphotericin B.

Topics: Amphotericin B; Animals; Disease Models, Animal; Humans; Leishmaniasis, Visceral; Liposomes; Mice; Mice, Inbred BALB C

Aspergillus terreus-induced invasive infections exhibit high lethality, partly due to the intrinsic resistance for amphotericin B (AmB). We compared the virulence and pathogenesis of an AmB-resistant isolate of A. terreus (ATR) with that of a rare variant showing enhanced sensitivity for AMB (ATS). The modifications that result in enhanced AmB sensitivity of isolates are not associated with reduced virulence in vivo; instead, the ATS-infected mice died even faster than the ATR-infected animals. Since A. terreus enters the blood stream in most patients and frequently induces thrombosis, we studied a putative correlation between virulence of the two A. terreus isolates and their effect on thrombocytes. Those mice infected with the more virulent ATS isolate had lower thrombocyte numbers and more phosphatidylserine exposure on platelets than ATR-infected mice. In vitro experiments confirmed that ATS and ATR differ in their effect on thrombocytes. Conidia, aleurioconidia and hyphae of ATS were more potent than ATR to trigger thrombocyte stimulation, and thrombocytes adhered better to ATS than to ATR fungal structures. Furthermore, ATS secreted more soluble factors that triggered platelet stimulation than ATR. Thus, it might be suggested that the capacity of a fungal isolate to modulate thrombocyte parameters contributes to its virulence in vivo.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus; Blood Platelets; Cell Adhesion; Disease Models, Animal; Drug Resistance, Fungal; Female; Healthy Volunteers; Humans; Mice; Mice, Inbred BALB C; Survival Analysis; Thrombocytopenia; Virulence

The aim of the present study was to evaluate the effects of amphotericin B (AMB) on clinical isolates of Aspergillus flavus.. MICs of both standard AMB and liposomal AMB (L-AMB) were determined using a broth dilution method for seven isolates of A. flavus. AMB MICs were also determined using the Etest. The activity of the polyene was then investigated in a murine model of systemic aspergillosis in which animals were infected intravenously, treated intravenously with several doses of the polyene (1-10 mg/kg/day) and observed for survival.. Broth dilution AMB, broth dilution L-AMB and Etest AMB MICs ranged from 0.5 to 2.0 mg/L, 0.06 to >16 mg/L and 1.0 to >32 mg/L, respectively. There were two isolates for which all doses were effective at prolonging the survival. Their AMB MICs were ≤1.0 mg/L, regardless of the method/drug formulation utilized for testing. There were four isolates for which no regimen was effective. Their broth dilution AMB, broth dilution L-AMB and Etest AMB MICs ranged from 1.0 to 2.0 mg/L, 0.06 to >16 mg/L and 2.0 to >32 mg/L, respectively. There was one isolate for which only L-AMB given at 10 mg/kg/day was effective; broth dilution MICs of AMB and L-AMB were 0.5 mg/L, while the Etest MIC of AMB was 2.0 mg/L.. Our data indicate that not all isolates of A. flavus should be considered resistant to AMB. The Etest represented the in vitro method that best correlated with the experimental infection. Finally, a clinical isolate showing an MIC ≥2.0 mg/L may be reasonably considered resistant in vivo to any dose/formulation of the polyene.

Topics: Administration, Intravenous; Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus flavus; Disease Models, Animal; Drug Resistance, Fungal; Female; Mice; Microbial Sensitivity Tests; Polyenes; Survival Analysis; Treatment Outcome

Amphotericin B (AmB), the most effective drug against leishmaniasis, has serious toxicity. As Leishmania species are obligate intracellular parasites of antigen presenting cells (APC), an immunopotentiating APC-specific AmB nanocarrier would be ideally suited to reduce the drug dosage and regimen requirements in leishmaniasis treatment. Here, we report a nanocarrier that results in effective treatment shortening of cutaneous leishmaniasis in a mouse model, while also enhancing L. major specific T-cell immune responses in the infected host.. We used a Pan-DR-binding epitope (PADRE)-derivatized-dendrimer (PDD), complexed with liposomal amphotericin B (LAmB) in an L. major mouse model and analyzed the therapeutic efficacy of low-dose PDD/LAmB vs full dose LAmB.. PDD was shown to escort LAmB to APCs in vivo, enhanced the drug efficacy by 83% and drug APC targeting by 10-fold and significantly reduced parasite burden and toxicity. Fortuitously, the PDD immunopotentiating effect significantly enhanced parasite-specific T-cell responses in immunocompetent infected mice.. PDD reduced the effective dose and toxicity of LAmB and resulted in elicitation of strong parasite specific T-cell responses. A reduced effective therapeutic dose was achieved by selective LAmB delivery to APC, bypassing bystander cells, reducing toxicity and inducing antiparasite immunity.

Topics: Adaptive Immunity; Amphotericin B; Animals; Antigen-Presenting Cells; Antiprotozoal Agents; Dendrimers; Disease Models, Animal; Drug Carriers; Epitopes; Female; Injections, Intraperitoneal; Leishmania major; Leishmaniasis Vaccines; Leishmaniasis, Cutaneous; Macrophages, Peritoneal; Malaria Vaccines; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Microscopy, Electron, Transmission; Nanoparticles

Candida albicans is the most common fungal pathogen. Galleria mellonella is widely used as an infection model host. Nevertheless, the G. mellonella-C. albicans infection model had not been optimized for drug evaluation before this study. In this work, we revealed that 5 × 10(5) colony forming unit (CFU)/larva was a suitable inoculum to optimize the G. mellonella-C. albicans infection model in order to evaluate antifungal agents. Using our optimized model, the antifungal effect of fluconazole, amphotericin B and flucytosine, and the synergy between amphotericin B and flucytosine were successfully verified. Thus, this study provides a rapid, inexpensive and reliable way to evaluate antifungals in vivo.

Topics: Amphotericin B; Animals; Antifungal Agents; Candida albicans; Disease Models, Animal; Fluconazole; Flucytosine; Larva; Moths

Candida albicans causes opportunistic systemic infections with high mortality (30%-50%). Despite significant nephrotoxicity, amphotericin (AmB) is still used for the treatment of this serious fungal infection. Therefore, alternative treatments are urgently needed. Dialyzable leukocyte extracts have been used successfully to treat patients with mucocutaneous candidiasis, but their effectiveness in systemic candidiasis has not been evaluated. In this study, low-dose AmB (0.1 mg/kg) plus 10 pg of murine dialyzable spleen extracts (mDSE) were tested in a systemic candidiasis mouse model. Survival, tissue fungal burden, kidney damage, kidney cytokines, and serum levels of IL-6 and hepcidin were evaluated. Our results showed that the combined treatment of low-dose AmB plus mDSE improved survival and reduced kidney fungal burden and histopathology; these effects correlated with increased kidney concentration of IFN- γ and TGF- β 1, decreased levels of TNF- α , IL-6, and IL-10, as well as high levels of systemic IL-6 and hepcidin. Low-dose AmB and mDSE synergized to clear the infectious agent and reduced tissue damage, confirming the efficacy of a low dose of AmB, which might decrease the risk of drug toxicity. Further studies are necessary to explore these findings and its implications in future therapeutic approaches.

Topics: Amphotericin B; Animals; Antifungal Agents; Candidiasis; Cytokines; Disease Models, Animal; Female; Hepcidins; Interleukin-6; Kidney; Lymphokines; Mice; Spleen

The evolution of drug resistance in microbial pathogens provides a paradigm for investigating evolutionary dynamics with important consequences for human health. Candida albicans, the leading fungal pathogen of humans, rapidly evolves resistance to two major antifungal classes, the triazoles and echinocandins. In contrast, resistance to the third major antifungal used in the clinic, amphotericin B (AmB), remains extremely rare despite 50 years of use as monotherapy. We sought to understand this long-standing evolutionary puzzle. We used whole genome sequencing of rare AmB-resistant clinical isolates as well as laboratory-evolved strains to identify and investigate mutations that confer AmB resistance in vitro. Resistance to AmB came at a great cost. Mutations that conferred resistance simultaneously created diverse stresses that required high levels of the molecular chaperone Hsp90 for survival, even in the absence of AmB. This requirement stemmed from severe internal stresses caused by the mutations, which drastically diminished tolerance to external stresses from the host. AmB-resistant mutants were hypersensitive to oxidative stress, febrile temperatures, and killing by neutrophils and also had defects in filamentation and tissue invasion. These strains were avirulent in a mouse infection model. Thus, the costs of evolving resistance to AmB limit the emergence of this phenotype in the clinic. Our work provides a vivid example of the ways in which conflicting selective pressures shape evolutionary trajectories and illustrates another mechanism by which the Hsp90 buffer potentiates the emergence of new phenotypes. Developing antibiotics that deliberately create such evolutionary constraints might offer a strategy for limiting the rapid emergence of drug resistance.

Topics: Amphotericin B; Animals; Biological Evolution; Candida albicans; Candidiasis; Disease Models, Animal; Drug Resistance, Fungal; Ergosterol; Fungal Proteins; Genetic Fitness; Host-Pathogen Interactions; HSP90 Heat-Shock Proteins; Humans; Mice; Microbial Sensitivity Tests; Microbial Viability; Mutation; Reproducibility of Results; Stress, Physiological; Virulence

The efficacy of antifungal prophylaxis for prevention of invasive aspergillosis (IA) may depend on whether IA results from recent inhalation of spores or reactivation of latent colonisation. Compare the efficacy of liposomal amphotericin B (LAmB) for prophylaxis in acute and reactivation models of IA. In the acute model, mice immunosuppressed from day 0 were challenged at day 3 with an aerosol of Aspergillus fumigatus. LAmB (15 mg kg(-1) ) was administered at day 0 or at challenge. In the reactivation model, naïve mice exposed to A. fumigatus remained untreated until clearance of spores from the lungs, then immunosuppressed to induce reactivation. A single LAmB dose was administered at start of immunosuppression. In the acute model, a single administration of LAmB at start of immunosuppression was not effective, but an additional administration resulted in a significant decrease in lung fungal burden (P < 0.05 vs. controls). A significant prophylactic efficacy was observed when LAmB was administered once at challenge (P < 0.01). In the reactivation model, a single LAmB administration at start of immunosuppression significantly reduced both reactivation rate and fungal burden vs. controls (P < 0.01). Our results show that the conditions under which IA develop and timing of administration of LAmB were determinant variables for prophylactic efficacy.

Topics: Acute Disease; Amphotericin B; Animals; Antibiotic Prophylaxis; Antifungal Agents; Aspergillus fumigatus; Disease Models, Animal; Drug Evaluation, Preclinical; Female; Immunocompromised Host; Invasive Pulmonary Aspergillosis; Lung; Mice; Mice, Inbred BALB C; Neutropenia; Spores, Fungal

In invasive pulmonary aspergillosis, direct invasion and occlusion of pulmonary vasculature by Aspergillus hyphae causes tissue hypoxia, which is enhanced by secreted fungal metabolites that downregulate compensatory angiogenic signaling pathways. We assessed the effects of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) on survival rates, fungal burden, and in situ angiogenesis in a murine invasive pulmonary aspergillosis model. bFGF and VEGF monotherapy significantly increased survival rates and potentiated the activity of amphotericin B. bFGF-containing regimens were associated with reduced tissue fungal burdens. bFGF and VEGF reversed the antiangiogenic activity of Aspergillus fumigatus; however, VEGF induced the formation of immature neovessels, providing an explanation for its lesser efficacy. Treatment with bFGF plus amphotericin B was associated with neutrophil influx into Aspergillus-infected pulmonary tissue, suggesting that this combination limits fungal growth through neutrophil trafficking. Vasculogenic pathways are unexplored targets for the treatment of invasive pulmonary aspergillosis and may potentiate both innate immunity and antifungal drug activity against A. fumigatus.

Topics: Amphotericin B; Angiogenesis Inducing Agents; Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Disease Models, Animal; Drug Evaluation, Preclinical; Drug Therapy, Combination; Female; Fibroblast Growth Factor 2; Humans; Immunohistochemistry; Lung; Lung Diseases, Fungal; Mice; Mice, Inbred BALB C; Microbial Sensitivity Tests; Neovascularization, Physiologic; Neutrophils; Recombinant Proteins; Survival Analysis; Vascular Endothelial Growth Factor A

Aspergillus terreus is considered to be resistant to amphotericin B (AMB). However, it is unknown whether higher daily doses of liposomal AMB (L-AMB) can overcome this resistance in vivo. We evaluated the efficacy and total lung homogenate AMB concentrations of escalating intravenous doses of L-AMB (3-20 mg/kg daily) versus an induction-de-escalation dosing strategy (10 mg/kg/day ×3 days, then 3 mg/kg/day) in an experimental neutropenic murine model of A. terreus pneumonia.. BALB/c mice were rendered neutropenic with cyclophosphamide and administered cortisone acetate prior to intranasal inoculation (3.5 × 10(6) conidia) with A. terreus (Etest MIC 8 mg/L). Mice were then treated with L-AMB regimens for 5-7 days. The efficacy was assessed by animal survival and quantitative PCR lung fungal burden. Total AMB lung homogenate concentrations were determined by HPLC.. Compared with untreated controls, 10 mg/kg/day L-AMB prolonged survival (mean >7 versus 3-4 days, P < 0.003) and reduced A. terreus lung fungal burden (median log10 conidial DNA 5.0 versus 6.7, P < 0.05). Daily L-AMB regimens >10 mg/kg/day were associated with poorer survival and higher lung fungal burden. The induction-de-escalation strategy of 10 mg/kg/day ×3 days followed by 3 mg/kg/day was as effective as 10 mg/kg daily dosing, and resulted in higher mean AMB lung homogenate concentrations compared with a continuous 10 mg/kg regimen (23.2 ± 6.7 versus 16.4 ± 4.4 μg/g, P = 0.09).. A high-dose induction-de-escalation L-AMB dosing strategy was an effective treatment for experimental A. terreus pneumonia in neutropenic mice.

Topics: Administration, Intravenous; Amphotericin B; Animals; Antifungal Agents; Aspergillus; Disease Models, Animal; Female; Mice; Mice, Inbred BALB C; Neutropenia; Pulmonary Aspergillosis; Survival Analysis; Treatment Outcome

Hypersensitivity reactions to liposomal drugs, often observed with Doxil and AmBisome, can arise from activation of the complement (C) system by phospholipid bilayers. To understand the mechanism of this adverse immune reaction called C activation-related pseudoallergy (CARPA), we analyzed the relationship among liposome features, C activation in human serum in vitro, and liposome-induced cardiovascular distress in pigs, a model for human CARPA. Among the structural variables (surface charge, presence of saturated, unsaturated, and PEGylated phospholipids, and cisplatin vs. doxorubicin inside liposomes), high negative surface charge and the presence of doxorubicin were significant contributors to reactogenicity both in vitro and in vivo. Morphological analysis suggested that the effect of doxorubicin might be indirect, via distorting the sphericity of liposomes and, if leaked, causing aggregation. The parallelism among C activation, cardiopulmonary reactions in pigs, and high rate of hypersensitivity reactions to Doxil and AmBisome in humans strengthens the utility of the applied tests in predicting the risk of CARPA.. The authors studied complement activation-related pseudoallergy (CARPA) in a porcine model and demonstrate that high negative surface charge and drug effects leading to distortion of liposome sphericity might be the most critical factors leading to CARPA. The applied tests might be used to predict CARPA in humans.

Topics: Amphotericin B; Animals; Antibiotics, Antineoplastic; Complement Activation; Disease Models, Animal; Doxorubicin; Heart Arrest; Humans; Hypersensitivity; Liposomes; Phospholipids; Polyethylene Glycols; Surface Properties; Swine

The purpose of this study was to investigate the performance of non-invasive diagnostic tests such as galactomannan enzyme immunoassay and quantitative PCR in the early diagnosis of invasive aspergillosis (IA), and how these tests are impacted upon by the use of different classes of antifungal agents in an in-vivo model of IA.. A standardised rat inhalation model of IA was used to examine the effects of an azole, posaconazole, a polyene, amphotericin B and an echinocandin caspofungin. Daily blood samples were collected for subsequent analysis using a commercially available galactomannan assay and an inhouse qPCR assay.. No significant differences were observed in the CE/g of Aspergillus fumigatus in the lungs of each group. qPCR was statistically more sensitive than galactomannan for both the early detection of infected controls (p=0.045) and for overall detection (p=0.018). However, antifungal treatment significantly reduced the overall sensitivity of qPCR (p=0.020); these effects were due to posaconazole and caspofungin. In the latter stages of infection (days 4 and 5) there were no significant differences in the numbers of infections detected by galactomannan and qPCR; however, the antifungal class used caused significant qualitative differences (p=0.041). Galactomannan showed improved detection in posaconazole-treated animals.. Previous exposure to antifungal therapy must be considered when interpreting either qPCR or galactomannan-based IA diagnostics as this study has shown that individual classes of antifungal agents impact upon the dynamics of antigen and DNA release into the circulation.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillus fumigatus; Biomarkers; Caspofungin; Disease Models, Animal; DNA, Fungal; Early Diagnosis; Echinocandins; Galactose; Immunoenzyme Techniques; Invasive Pulmonary Aspergillosis; Lipopeptides; Mannans; Microbiological Techniques; Mycological Typing Techniques; Predictive Value of Tests; Rats; Real-Time Polymerase Chain Reaction; Time Factors; Triazoles

Cryptococcosis is a subacute or chronic systemic mycosis with a cosmopolitan nature, caused by yeast of the genus Cryptococcus neoformans. The model of systemic cryptococcosis in mice with severe combined immunodeficiency (SCID) is useful for immunological and therapeutic study of the disease in immunodeficient hosts. Amphotericin B, fluconazole and flucytosine are the drugs most commonly used to treat cryptococcosis. Voriconazole is a triazole with high bioavailability, large distribution volume, and excellent penetration of the central nervous system. The objective of this study was to evaluate treatment with amphotericin B (AMB), voriconazole (VRC), and AMB, used in combination with VRC, of experimental pulmonary cryptococcosis in a murine model (SCID). The animals were inoculated intravenously (iv) with a solution containing 3.0 × 10(5) viable cells of C. neoformans ATCC 90112, (serotype A). Treatments were performed with amphotericin B (1.5 mg/kg/day), voriconazole (40.0 mg/kg/day) and AMB (1.5 mg/kg/day) combined with VRC (40.0 mg/kg/day); began 1 day after the initial infection; were daily; and lasted 15 days. Evaluations were performed using analysis of the survival curve and isolation of yeast in the lung tissue. There was a significant increase in survival in groups treated with AMB combined with VRC, compared with the untreated group and groups receiving other treatments (P < 0.05). In the group treated only with VRC and AMB combined with VRC, there was a significant reduction (P < 0.05) in the isolation of C. neoformans in lung tissue. Amphotericin B combined with voriconazole may be an effective alternative to increasing survival and may reduce yeast in the lung tissue of mice with pulmonary cryptococcosis and SCID.

Topics: Amphotericin B; Animals; Antifungal Agents; Cryptococcosis; Cryptococcus neoformans; Disease Models, Animal; Drug Therapy, Combination; Lung; Lung Diseases, Fungal; Mice; Mice, SCID; Pyrimidines; Severe Combined Immunodeficiency; Survival Analysis; Treatment Outcome; Triazoles; Voriconazole

Meningitis is one of the most fatal manifestations of cryptococcosis, even with specific treatment. Combination of a prompt diagnosis and appropriate therapy are critical to reduce the fungal load and the inflammatory response effects of the proliferation of yeast into the central nervous system (CNS). Mice with experimental acute meningitis caused by Cryptococcus neoformans were treated with liposomal amphotericin B (L-AmB) administered intrathecally (i.t.c.) at 0.006 mg/kg weekly or intravenously (i.v.) at 10 mg/kg daily or with voriconazole (VCZ) administered orally at 30 mg/kg per dose twice daily or with combinations of both drugs, i.e. L-AmB i.t.c.+VCZ or L-AmB i.v.+VCZ at the same doses as used in the monotherapies. All treatments significantly increased the survival of animals in comparison with the control group, with VCZ being less effective in comparison with all other treatments (P ≤ 0.012). All treatments, with the exception of VCZ (P=0.533), reduced fungal burdens in the brain in comparison with controls. The combination of L-AmB i.t.c.+VCZ showed a synergistic effect in the reduction of fungal load that was significantly superior to any tested therapy (P ≤ 0.039). Histologically, untreated animals showed a marked inflammatory response with massive fungal cells in the meninges, whilst treated animals showed a variable number of fungal cells in the CNS, with the exception of animals receiving L-AmB i.t.c.+VCZ in which neither yeasts nor inflammation were observed.

Topics: Amphotericin B; Animals; Antifungal Agents; Brain; Colony Count, Microbial; Cryptococcus neoformans; Disease Models, Animal; Drug Evaluation, Preclinical; Drug Synergism; Drug Therapy, Combination; Injections, Spinal; Male; Meningitis, Cryptococcal; Mice; Pyrimidines; Triazoles; Voriconazole

Amphotericin B inhalation powder (ABIP) is a novel dry-powder amphotericin B formulation that is directly delivered to the lung, resulting in elevated lung tissue drug concentrations of this polyene. We evaluated the prophylactic efficacy of single dose administration of ABIP in a guinea pig model of invasive pulmonary aspergillosis.. Guinea pigs were immunosuppressed with cyclophosphamide and cortisone acetate and challenged with Aspergillus fumigatus conidia in an aerosol chamber. Guinea pigs received prophylaxis with a single inhaled dose of ABIP at 0.05, 0.5, 4 or 10 mg/kg administered 24 h prior to infection. Treatment with oral voriconazole at doses of 5 or 10 mg/kg twice daily beginning 24 h post-challenge served as the positive control.. Improvements in survival were observed with ABIP prophylaxis. A single inhaled dose of 4 mg/kg ABIP and treatment with 5 mg/kg voriconazole both improved median and percentage survival compared with untreated controls. In addition, pulmonary fungal burden, as assessed by cfu, quantitative PCR and galactomannan, was also reduced in a dose-dependent fashion with ABIP prophylaxis as well as with both doses of voriconazole treatment.. Single-dose prophylaxis with inhaled ABIP as prophylaxis demonstrated a significant survival advantage and reductions in pulmonary fungal burden in this model of invasive pulmonary aspergillosis. Optimization of the dose and dosing frequency of ABIP dose may help to further enhance the anti-Aspergillus activity of this novel amphotericin B formulation.

Topics: Administration, Inhalation; Amphotericin B; Animals; Antifungal Agents; Aspergillus fumigatus; Chemoprevention; Colony Count, Microbial; Cortisone; Cyclophosphamide; Disease Models, Animal; Guinea Pigs; Immunosuppressive Agents; Invasive Pulmonary Aspergillosis; Lung; Male; Pyrimidines; Survival Analysis; Triazoles; Voriconazole

The in vitro susceptibility of 17 strains of Mucor circinelloides to amphotericin B and posaconazole was ascertained by using broth microdilution and disk diffusion methods and by determining the minimal fungicidal concentration (MFC). We evaluated the efficacy of posaconazole at 40 mg/kg of body weight/day and amphotericin B at 0.8 mg/kg/day in a neutropenic murine model of disseminated infection by M. circinelloides by using 6 different strains tested previously in vitro. In general, most of the posaconazole MICs were within the range of susceptibility or intermediate susceptibility, while the small inhibition zone diameters (IZDs) were indicative of nonsusceptibility for all isolates tested. The MFCs were ≥ 3 dilutions higher than the corresponding MICs. In contrast, amphotericin B showed good activity against all of the strains tested regardless of the method used. The in vivo studies demonstrated that amphotericin B was effective in prolonging survival and reducing the fungal load. Posaconazole showed poor in vivo efficacy with no correlation with the MIC values. The results suggested that posaconazole should be used with caution in the treatment of infections caused by Mucor circinelloides or by strains of Mucor not identified to the species level.

Topics: Amphotericin B; Animals; Antifungal Agents; Brain; Disease Models, Animal; Drug Resistance, Fungal; Kidney; Male; Mice; Microbial Sensitivity Tests; Mucor; Mucormycosis; Neutropenia; Species Specificity; Survival Rate; Treatment Failure; Triazoles

We developed a murine model of systemic sporotrichosis by using three strains of each of the two commonest species causing sporotrichosis, i.e., Sporothrix schenckii sensu stricto and Sporothrix brasiliensis, in order to evaluate the efficacy of posaconazole (PSC). The drug was administered at a dose of 2.5 or 5 mg/kg of body weight twice a day by gavage, and one group was treated with amphotericin B (AMB) as a control treatment. Posaconazole, especially at 5 mg/kg, showed good efficacy against all the strains tested, regardless of their MICs, as measured by prolonged survival, tissue burden reduction, and histopathology.

Topics: Administration, Oral; Amphotericin B; Animals; Antifungal Agents; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Administration Schedule; Histocytochemistry; Liver; Male; Mice; Microbial Sensitivity Tests; Species Specificity; Sporothrix; Sporotrichosis; Survival Rate; Treatment Outcome; Triazoles

We evaluated the in vitro activity of posaconazole and amphotericin B against several clinical strains of the mucoralean fungus Apophysomyces variabilis, and their efficacy in a murine model of disseminated infection caused by that fungus.. The in vitro susceptibility of seven strains of A. variabilis to posaconazole and amphotericin B was determined by using a broth microdilution method. The in vivo efficacy of both drugs, posaconazole at 20 mg/kg twice daily orally by gavage and amphotericin B at 0.8 mg/kg once daily intravenously, was evaluated against six of the strains previously tested in vitro using immunocompetent mice.. In general, MICs of both drugs were within the range of susceptibility or intermediate susceptibility. Posaconazole and amphotericin B were able to significantly reduce the percentages of positive cultures in the affected tissues. However, in general, posaconazole significantly improved survival (median, 23 days; range, 7-30 days) compared with untreated controls (median, 6 days; range, 4-7 days) and, in some cases, with respect to the animals treated with amphotericin B (median, 15 days; range, 5-30 days).. Our results demonstrate the efficacy of posaconazole in the treatment of a disseminated murine infection caused by A. variabilis. However, further clinical studies are required to ascertain the potential use in human infections caused by this fungus.

Topics: Amphotericin B; Animals; Antifungal Agents; Disease Models, Animal; Humans; Injections, Intravenous; Male; Mice; Microbial Sensitivity Tests; Mucorales; Mucormycosis; Treatment Outcome; Triazoles

We have determined the in vitro activity of amphotericin B (AMB) and posaconazole (PSC) against Saksenaea vasiformis using broth microdilution and disk diffusion methods and determined the minimal fungicidal concentration (MFC). PSC was found to have the greatest in vitro activity in all cases and was the most efficacious in prolonging survival and reducing the fungal load in an immunocompetent murine model of disseminated infection caused by four strains of the fungus.

Topics: Amphotericin B; Animals; Antifungal Agents; Disease Models, Animal; Male; Mice; Microbial Sensitivity Tests; Mucorales; Mucormycosis; Treatment Outcome; Triazoles

Amphotericin B (AMB) is used to treat both fungal and leishmanial infections, which are of major significance to human health. Clinical use of free AMB is limited by its nephrotoxicity, whereas liposomal AMB is costly and requires parenteral administration, thus development of novel formulations with enhanced efficacy, minimal toxicity and that can be applied via non-invasive routes is required. In this study we analysed the potential of non-ionic surfactant vesicles (NIV) given by nebulisation to deliver AMB to the lungs, liver and skin. Treatment with AMB-NIV resulted in significantly higher drug levels in the lungs and skin (p<0.05) compared to similar treatment with AMB solution but significantly lower plasma levels (p<0.05). Treatment with AMB-NIV resulted in a significant reduction in fungal lung burdens in a rat model of invasive pulmonary aspergillosis (p<0.05) compared to treatment with the carrier alone. Treatment with AMB-NIV but not AMB solution significantly suppressed Leishmania donovani liver parasite burdens (p<0.05) but could not inhibit the growth of cutaneous Leishmania major lesions. The results of this study indicate that aerosolised NIV enhanced pulmonary and hepatic delivery whilst minimising systemic exposure and toxicity.

Topics: Aerosols; Amphotericin B; Animals; Antifungal Agents; Cricetinae; Disease Models, Animal; Drug Carriers; Female; Firefly Luciferin; Leishmaniasis; Liver; Lung; Mesocricetus; Mice; Mice, Inbred BALB C; Pulmonary Aspergillosis; Rats; Rats, Sprague-Dawley; Surface-Active Agents

The efficacy of fluconazole (FLU), amphotericin B (AMB) and caspofungin (CAS) was tested against three Candida orthopsilosis, three C. metapsilosis and two C. parapsilosis sensu stricto isolates in neutropenic mice.. Mice were immunosuppressed by 200 mg/kg cyclophosphamide. Five-day intraperitoneal treatment was started 24 h after infection. Kidney burden was analyzed using the Kruskal-Wallis test.. FLU 10 and 20 mg/kg as well as AMB 1 mg/kg significantly decreased the fungal burden (p < 0.05) for all eight isolates of the three species. CAS 2 and 5 mg/kg were efficacious against all C. orthopsilosis and C. metapsilosis isolates (p < 0.05), but only 5 mg/kg CAS was effective against C. parapsilosis isolates (p < 0.05).. The efficacy of FLU and AMB against the three species was comparable. Though the activity of CAS was higher against C. orthopsilosis and C. metapsilosis, the current treatment guidelines for C. parapsilosis sensu stricto seem to be applicable to other 'psilosis' species.

Topics: Amphotericin B; Animals; Antifungal Agents; Candida; Caspofungin; Disease Models, Animal; Echinocandins; Female; Fluconazole; Immunocompromised Host; Kidney; Lipopeptides; Mice; Mice, Inbred BALB C; Microbial Sensitivity Tests; Neutropenia

Fusarium is a major cause of microbial keratitis, and its ability to form biofilms was suggested as a contributing factor in recent outbreaks. We investigated the ability of outbreak Fusarium isolates (F. solani species complex [FSSC] and F. oxysporum species complex [FOSC]) to form biofilms in vitro and in vivo, and evaluated their antifungal susceptibilities.. Biofilm formation was assessed using our in vitro contact lens model and in vivo murine model. Biofilm architecture was assessed using confocal laser scanning microscopy (CLSM). Susceptibility against amphotericin B (AmB), voriconazole (VCZ), and natamycin (NAT) was determined using the CLSI-M38-A2 method and XTT metabolic assay.. FSSC strains formed more biofilms than FOSC, in a strain- and clade-dependent manner. CLSM analyses revealed that "high biofilm forming" (HBF) strains had denser and thicker biofilms than "low biofilm forming" (LBF) strains of both species (thickness 51 vs. 41 μm for FSSC and 61 vs. 45 μm for FOSC strains, P < 0.05 for both comparisons). Fusarium biofilms exhibited species-dependent antifungal susceptibilities (e.g., FSSC biofilms AmB minimal inhibitory concentrations [MIC] ≥16 μg/mL, while NAT or VCZ MICs were 2-8 μg/mL). FSSC-infected mice had severe corneal opacification independent of biofilm thickness, while FOSC infection resulted in moderate corneal opacification. Corneal fungal burden of mice infected with HBF strains was higher than those of the LBF strains. In contrast, the reference ATCC isolate was unable to cause infection.. The ability to form biofilms is a key pathogenicity determinant of Fusarium, irrespective of the thickness of these biofilms. Further studies are warranted to explore this association in greater detail.

Topics: Amphotericin B; Animals; Antifungal Agents; Biofilms; Corneal Ulcer; Disease Models, Animal; Disease Outbreaks; Drug Resistance, Fungal; Epithelium, Corneal; Eye Infections, Fungal; Fusariosis; Fusarium; Mice; Mice, Inbred C57BL; Microbial Sensitivity Tests; Microscopy, Confocal; Natamycin; Pyrimidines; Triazoles; Virulence; Voriconazole

To investigate the correlation between in vitro killing activity and in vivo efficacy of micafungin (MCFG) and liposomal amphotericin B (L-AMB) against Candida tropicalis in a neutropenic murine lethal infection model.. Candida albicans (one strain) and C. tropicalis (three strains) were tested in time-kill studies. Cyclophosphamide-treated mice were inoculated intravenously with each strain. One day after inoculation, antifungals were administered intravenously once daily for 1 or 3 days.. MCFG exhibited fungicidal activity against C. albicans ATCC 90029 and C. tropicalis SP-20142, and fungistatic activity against C. tropicalis ATCC 42678 and SP-20047. The ED(50)s (dosage that results in 50% survival) of MCFG for C. tropicalis ATCC 42678 and SP-20047 (4.1-50 mg/kg) were higher than those for other strains (1.6-12 mg/kg). A 1-day course of MCFG was not effective against C. tropicalis ATCC 42678 and SP-20047 at the clinical dose (5 mg/kg), which achieved an AUC level almost equal to that of 100 mg in humans, whereas a 3-day course of 5 mg/kg MCFG was efficacious against all strains. In contrast, L-AMB showed fungicidal activity against all strains tested and the ED(50)s of L-AMB were 0.08-0.65 mg/kg. In both treatment regimens, the minimum effective doses of L-AMB (≤0.5 mg/kg) were less than the clinical dosage (≤5 mg/kg).. The in vivo efficacy of MCFG and L-AMB showed a correlation with the in vitro killing activity. At the clinical dose, L-AMB exerted anti-C. tropicalis activity within a shorter treatment period than MCFG.

Topics: Amphotericin B; Animals; Antifungal Agents; Area Under Curve; Candida tropicalis; Candidiasis; Disease Models, Animal; Echinocandins; Lipopeptides; Male; Micafungin; Mice; Microbial Sensitivity Tests; Neutropenia

The present work aimed to investigate the curative effect of benznidazole (BZL) in combination with other patented drugs [nifurtimox (NFX), posaconazole (POS) or AmBisome(®) (AMB)] in mice acutely or chronically infected with either a BZL-susceptible (Tulahuen) or a BZL-partially-resistant (Y) strain of Trypanosoma cruzi. To appreciate the eventual advantage of such combinations, infected mice were treated for short durations (non-curative) of each individual treatment. Cure rates were determined by investigating blood parasites (microscopic examination) and parasite DNA (quantitative PCR) after submitting treated mice to immune suppression with cyclophosphamide. The results mainly suggest that shorter durations of treatment combining BZL and POS or NFX might cure mice acutely or chronically infected with the Tulahuen strain, whereas the combination of BZL with AMB does not have such an effect. Moreover, the association BZL+POS does not improve the curative effect of POS (all used for shorter durations) in infection with the Y strain. Shortening the duration of treatment whilst keeping a complete curative effect deserves interest in limiting adverse reactions due to dose-cumulative toxic effects of long treatment. Genotyping of the T. cruzi strain(s) infecting patients might also allow a better adaptation of individual therapeutic schedules, improving both the efficiency and safety of trypanocidal treatment. This preliminary experimental study should encourage further investigations to find the best combination of adequate drug concentrations and timing of treatment.

Topics: Amphotericin B; Animals; Chagas Disease; Disease Models, Animal; DNA, Protozoan; Drug Therapy, Combination; Female; Mice; Mice, Inbred BALB C; Nifurtimox; Nitroimidazoles; Parasite Load; Parasitemia; Real-Time Polymerase Chain Reaction; Treatment Outcome; Triazoles; Trypanocidal Agents; Trypanosoma cruzi

Substitution around 5-methyl benzothieno[3,2-b]quinolinium (2) ring system was explored in order to identify positions of substitution that could improve its antifungal profile. The 3-methoxy (10b) was active against C. albicans, C. neoformans, and A. fumigatus and the 4-chloro (10f) analog showed moderate increases in anti-cryptococcal and anti-aspergillus activities. The effectiveness of 10b and 10f were validated in murine models of candidiasis and cryptococcosis, respectively. The efficacy of 10f in reducing brain cryptococcal infection and its observation in the brain of mice injected with this quaternary compound confirm the capacity of these compounds to cross the blood-brain barrier of mice. Overall, several of the chloro and methoxy substituted compounds showed significant improvements in activity against A. fumigatus, the fungal pathogen prevalent in patients receiving organ transplant. Opening the benzothiophene ring of 2 to form 1-(5-cyclohexylpentyl)-3-(phenylthio)quinolinium compound (3) resulted in the identification of several novel compounds with over 50-fold increases in potency (cf. 2) while retaining low cytotoxicities. Thus, compound 3 constitutes a new scaffold for development of drugs against opportunistic infections.

Topics: Animals; Blood-Brain Barrier; Candidiasis; Chromatography, High Pressure Liquid; Disease Models, Animal; Fungi; In Vitro Techniques; Magnetic Resonance Spectroscopy; Maximum Tolerated Dose; Mice; Microbial Sensitivity Tests; Quinolines

Treatment of diseases such as African sleeping sickness and leishmaniasis often depends on relatively expensive or toxic drugs, and resistance to current chemotherapeutics is an issue in treating these diseases and malaria. In this study, a new semi-synthetic berberine analogue, 5,6-didehydro-8,8-diethyl-13-oxodihydroberberine chloride (1), showed nanomolar level potency against in vitro models of leishmaniasis, malaria, and trypanosomiasis as well as activity in an in vivo visceral leishmaniasis model. Since the synthetic starting material, berberine hemisulfate, is inexpensive, 8,8-dialkyl-substituted analogues of berberine may lead to a new class of affordable antiprotozoal compounds.

Topics: Animals; Antiprotozoal Agents; Berberine; Chlorocebus aethiops; Disease Models, Animal; Inhibitory Concentration 50; Leishmania; Leishmaniasis; Malaria; Mice; Models, Molecular; Parasites; Plasmodium falciparum; Protozoan Infections; Trypanosoma brucei brucei; Trypanosomiasis; Vero Cells

Using a murine model of disseminated infection by Fusarium verticillioides, the efficacy of liposomal amphotericin (L-AmB) B at 10mg/kg body weight once daily and terbinafine (TRB) at 150 mg/kg body weight twice daily, alone and in combination, was evaluated. The combination of L-AmB with TRB was the only treatment able to prolong survival and to reduce fungal loads in the spleen and kidneys of mice infected with either strain of F. verticillioides used. The results suggest that this combination may have a role in the treatment of F. verticillioides infection.

Topics: Amphotericin B; Animals; Antifungal Agents; Colony Count, Microbial; Disease Models, Animal; Drug Therapy, Combination; Fusarium; Kidney; Male; Mice; Mycoses; Naphthalenes; Spleen; Survival Analysis; Terbinafine; Treatment Outcome

The therapeutic efficacy of amphotericin B and voriconazole alone and in combination with one another were evaluated in immunodeficient mice (BALB/c-SCID) infected with a fluconazole-resistant strain of Cryptococcus neoformans var. grubii. The animals were infected intravenously with 3 × 10(5) cells and intraperitoneally treated with amphotericin B (1.5 mg/kg/day) in combination with voriconazole (40 mg/kg/days). Treatment began 1 day after inoculation and continued for 7 and 15 days post-inoculation. The treatments were evaluated by survival curves and yeast quantification (CFUs) in brain and lung tissues. Treatments for 15 days significantly promoted the survival of the animals compared to the control groups. Our results indicated that amphotericin B was effective in assuring longest-term survival of infected animals, but these animals still harbored the highest CFU of C. neoformans in lungs and brain at the end of the experiment. Voriconazole was not as effective alone, but in combination with amphotericin B, it prolonged survival for the second-longest time period and provided the lowest colonization of target organs by the fungus. None of the treatments were effective in complete eradication of the fungus in mice lungs and brain at the end of the experiment.

Topics: Amphotericin B; Animals; Antifungal Agents; Brain; Colony Count, Microbial; Cryptococcosis; Cryptococcus neoformans; Disease Models, Animal; Drug Resistance, Fungal; Drug Therapy, Combination; Fluconazole; Lung; Mice; Mice, Inbred BALB C; Mice, SCID; Pyrimidines; Rodent Diseases; Survival Analysis; Treatment Outcome; Triazoles; Voriconazole; Yeasts

To construct a suitable ex vivo model for the research of molecular mechanisms and the pharmacological screening of fungal adherence on the corneal surface.. Mouse eyes were divided into three groups as follows: a control group with normal corneal epithelium, a group with corneal epithelium that was needle-scarified, and a group with corneal epithelium that was completely debrided. All 96 corneas were placed in organ culture and inoculated with 5 μl spore suspensions of Candida albicans at 10⁹, 10⁸, or 10⁷ colony-forming units (CFU)/ml and incubated for 0, 30, 60, or 120 min. The corneas were homogenated and diluted for quantification by counting the CFU. The effects of amphotericin B or chondroitin sulfate on the adherence of the fungal spores were evaluated with the ex vivo organ culture model and were also compared with the human corneal epithelium monolayer model in vitro.. Compared with the normal corneas with intact epithelium, the corneas with scarified and debrided epithelium adhered more spores for above two and four folds. The spore adhesion on the corneal surface was in an inoculation concentration- and incubation time-dependent manner. Moreover, both amphotericin B and chondroitin sulfate inhibited the adhesion of C. albicans spores on the corneal surface, but the inhibitory rates were different between the ex vivo corneal organ culture model and the in vitro corneal epithelium monolayer model.. The corneal organ culture was a suitable ex vivo model for the research of fungal adhesion mechanisms and drug screening.

Topics: Amphotericin B; Animals; Bacterial Adhesion; Candida albicans; Candidiasis; Chondroitin Sulfates; Colony Count, Microbial; Cornea; Corneal Injuries; Corneal Ulcer; Disease Models, Animal; Eye Infections, Fungal; Mice; Mice, Inbred BALB C; Organ Culture Techniques; Time Factors

Liposomal amphotericin B (LAmB) combined wither either micafungin or deferasirox was synergistic in previous murine studies with mucormycosis or aspergillosis. We hypothesized that triple therapy using LAmB, micafungin, and deferasirox could further improve outcomes of mucormycosis or aspergillosis. Triple therapy improved survival and reduced tissue fungal burden of mice with mucormycosis and to a lesser extent with aspergillosis. Continued investigation into the use of triple therapy against mucormycosis and aspergillosis is warranted.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Disease Models, Animal; Echinocandins; Iron Chelating Agents; Lipopeptides; Micafungin; Mice; Mice, Inbred BALB C; Mucormycosis; Polyenes; Rhizopus

Invasive pulmonary aspergillosis remains problematic in immunocompromised patient populations. We studied potential therapeutic options in a murine model of pulmonary aspergillosis in triamcinolone-suppressed DBA/2 mice infected intranasally with conidia from Aspergillus fumigatus. Mice were treated with liposomal-amphotericin B (AmBi; AmBisome), lipid-complexed amphotericin B (ABLC; Abelcet), voriconazole (VCZ), micafungin (MICA), caspofungin (CAS) or deoxycholate amphotericin B (AMBd) given alone or in combination. Monotherapy with AmBi, ABLC, AMBd, CAS or MICA had activity in prolonging survival; however, only AMBd or CAS reduced fungal burden in the lungs and kidneys. Combinations of AmBi plus CAS or MICA prolonged survival, but were not better than monotherapy. VCZ was ineffective and AMBd plus CAS showed a possible antagonism. AmBi or ABLC at higher dosages, or loading-doses of AmBi resulted in reduced survival. Histopathology showed increased incidence of serious renal and mild hepatic toxicity in triamcinolone-treated mice given an amphotericin B regimen compared to no or only triamcinolone (minimal renal changes occurred with CAS or VCZ with or without triamcinolone); suggestive of combined toxicity of triamcinolone and the amphotericin B in AmBi or ABLC. Infected treated mice showed progressive pulmonary disease including abscesses, angioinvasion and abundant intralesional fungi. High loading-doses of AmBi were associated with nephrosis and damage to other tissues. No monotherapy or combination regimen showed superiority for the treatment of pulmonary aspergillosis in corticosteroid suppressed mice and the potential for combined drug toxicity was enhanced in these mice. High dosages of lipid-formulated amphotericin B also proved unsatisfactory. Additional studies are needed to evaluate improved treatment.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillus fumigatus; Caspofungin; Colony Count, Microbial; Deoxycholic Acid; Disease Models, Animal; Drug Combinations; Drug Therapy, Combination; Echinocandins; Humans; Invasive Pulmonary Aspergillosis; Lipopeptides; Male; Micafungin; Mice; Mice, Inbred DBA; Pyrimidines; Triazoles; Voriconazole

Chagas disease is one of the most important public health problems and a leading cause of cardiac failure in Latin America. The currently available drugs to treat T. cruzi infection (benznidazole and nifurtimox) are effective in humans when administered during months. AmBisome (liposomal amphotericin B), already shown efficient after administration for some days in human and experimental infection with Leishmania, has been scarcely studied in T. cruzi infection.. This work investigates the effect of AmBisome treatment, administered in 6 intraperitoneal injections at various times during acute and/or chronic phases of mouse T. cruzi infection, comparing survival rates and parasitic loads in several tissues.. Quantitative PCR was used to determine parasitic DNA amounts in tissues. Immunosuppressive treatment with cyclophosphamide was used to investigate residual infection in tissues.. Administration of AmBisome during the acute phase of infection prevented mice from fatal issue. Parasitaemias (microscopic examination) were reduced in acute phase and undetectable in chronic infection. Quantitative PCR analyses showed significant parasite load reductions in heart, liver, spleen, skeletal muscle and adipose tissues in acute as well as in chronic infection. An earlier administration of AmBisome (one day after parasite inoculation) had a better effect in reducing parasite loads in spleen and liver, whereas repetition of treatment in chronic phase enhanced the parasite load reduction in heart and liver. However, whatever the treatment schedule, cyclophosphamide injections boosted infection to parasite amounts comparable to those observed in acutely infected and untreated mice.. Though AmBisome treatment fails to completely cure mice from T. cruzi infection, it impedes mortality and reduces significantly the parasitic loads in most tissues. Such a beneficial effect, obtained by administrating it over a short time, should stimulate studies on using AmBisome in association with other drugs in order to shorten recovery from T. cruzi infection.

Topics: Amphotericin B; Animal Structures; Animals; Antiprotozoal Agents; Chagas Disease; Disease Models, Animal; DNA, Protozoan; Humans; Injections, Intraperitoneal; Mice; Mice, Inbred BALB C; Polymerase Chain Reaction; Rodent Diseases; Survival Analysis; Trypanosoma cruzi

Cutaneous leishmaniasis (CL) is a neglected tropical disease that causes prominent skin scaring. No water soluble, non-toxic, short course and low cost treatment exists. We developed a new water soluble amphotericin B-polymethacrylic acid (AmB-PMA) using established and scalable chemistries. AmB-PMA was stable for 9 months during storage. In vitro, it was effective against Leishmania spp. promastigotes and amastigote infected macrophages. It was also less toxic and more effective than deoxycholate-AmB, and similar to liposomal AmB. Its in vivo activity was determined in both early and established CL lesion models of Leishmania major infection in genetically susceptible non-healing BALB/c mice. Intradermal AmB-PMA at a total dose of 18 mg of AmB/kg body weight led to rapid parasite killing and lesion healing. No toxicity was seen. No parasite relapse occurred after 80 days follow-up. Histological studies confirmed rapid parasite clearance from macrophages followed by accelerated fibroblast mediated tissue repair, regeneration and cure of the infection. Quantitative mRNA studies of the CL lesions showed that accelerated healing was associated with increased Tumour Necrosis Factor-α and Interferon-γ, and reduced Interleukin-10. These results suggest that a cost-effective AmB-PMA could be used to pharmacologically treat and immuno-therapeutically accelerate the healing of CL lesions.

Topics: Amphotericin B; Animals; Cell Line; Chemokines; Disease Models, Animal; Erythrocytes; Humans; Hypersensitivity, Delayed; Immunomodulation; Leishmania major; Leishmaniasis, Cutaneous; Macrophages; Mice; Mice, Inbred BALB C; Parasite Load; Polymethacrylic Acids; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Solubility; Spectrophotometry, Ultraviolet; Toxicity Tests; Water; Wound Healing

The in vivo efficacy of posaconazole against 4 clinical Aspergillus fumigatus isolates with posaconazole MICs ranging from 0.03 to 16 mg/liter, as determined by CLSI method M38A, was assessed in a nonneutropenic murine model of disseminated aspergillosis. The underlying resistance mechanisms of the isolates included substitutions in the cyp51A gene at codon 220 (M220I), codon 54 (G54W), and codon 98 (L98H). The latter was combined with a 34-bp tandem repeat in the gene promoter region (TR L98H). The control isolate exhibited a wild-type phenotype without any known resistance mechanism. Oral posaconazole therapy was started 24 h after infection and was given once daily for 14 consecutive days. Mice were treated with four different doses (1 to 64 mg/kg of body weight), and survival was used as the end point. Survival was dependent both on the dose and on the MIC. The Hill equation with a variable slope fitted the relationship between the dose/MIC ratio and 14-day survival well (R2, 0.92), with a 50% effective dose (ED50) of 29.0 mg/kg (95% confidence interval [CI], 15.6 to 53.6 mg/kg). This also applied to the relationship between the area under the plasma concentration-time curve (AUC)/MIC ratio and 14-day survival (50% effective pharmacodynamic index [EI50], 321.3 [95% CI, 222.7 to 463.4]). Near-maximum survival was reached at an AUC/MIC ratio of nearly 1,000. These results indicate that treatment of infections with A. fumigatus strains for which MICs are 0.5 mg/liter requires doses exceeding the present licensed doses. Increasing the standard dosing regimen may have some effect and may be clinically useful if no alternatives are available.

Topics: Administration, Oral; Animals; Antifungal Agents; Area Under Curve; Aspergillosis; Aspergillus fumigatus; Cytochrome P-450 Enzyme System; Disease Models, Animal; Drug Administration Schedule; Female; Fungal Proteins; Mice; Microbial Sensitivity Tests; Mutation; Triazoles

We have evaluated the efficacy of posaconazole, amphotericin B, and itraconazole in a murine model of disseminated infection by Fonsecaea monophora. Of these three antifungal drugs tested, posaconazole prolonged survival significantly and reduced the fungal load in most of the organs tested. Bioassay studies demonstrated the relationship between posaconazole levels and dose escalation in serum and brain tissue. Posaconazole may have a clinical role in the treatment of disseminated infections by F. monophora.

Topics: Animals; Antifungal Agents; Ascomycota; Brain; Disease Models, Animal; Kidney; Liver; Lung; Male; Mice; Mycoses; Triazoles

Arylimidamides (AIAs) represent a new class of molecules that exhibit potent antileishmanial activity (50% inhibitory concentration [IC(50)], <1 microM) against both Leishmania donovani axenic amastigotes and intracellular Leishmania, the causative agent for human visceral leishmaniasis (VL). A systematic lead discovery program was employed to characterize in vitro and in vivo antileishmanial activities, pharmacokinetics, mutagenicities, and toxicities of two novel AIAs, DB745 and DB766. They were exceptionally active (IC(50) < or = 0.12 microM) against intracellular L. donovani, Leishmania amazonensis, and Leishmania major and did not exhibit mutagenicity in an Ames screen. DB745 and DB766, given orally, produced a dose-dependent inhibition of liver parasitemia in two efficacy models, L. donovani-infected mice and hamsters. Most notably, DB766 (100 mg/kg of body weight/day for 5 days) reduced liver parasitemia in mice and hamsters by 71% and 89%, respectively. Marked reduction of parasitemia in the spleen (79%) and bone marrow (92%) of hamsters was also observed. Furthermore, these compounds distributed to target tissues (liver and spleen) and had a moderate oral bioavailability (up to 25%), a large volume of distribution, and an elimination half-life ranging from 1 to 2 days in mice. In a repeat-dose toxicity study of mice, there was no indication of liver or kidney toxicity for DB766 from serum chemistries, although mild hepatic cell eosinophilia, hypertrophy, and fatty changes were noted. These results demonstrated that arylimidamides are a promising class of molecules that possess good antileishmanial activity and desirable pharmacokinetics and should be considered for further preclinical development as an oral treatment for VL.

Topics: Amidines; Animals; Antiprotozoal Agents; Biological Availability; Cricetinae; Disease Models, Animal; Drug Discovery; Female; Furans; Humans; In Vitro Techniques; Leishmania donovani; Leishmania major; Leishmania mexicana; Leishmaniasis, Visceral; Liver; Mesocricetus; Mice; Mice, Inbred BALB C; Microsomes, Liver; Mutagenicity Tests; Parasitemia; Parasitic Sensitivity Tests; Spleen; Tissue Distribution

We evaluated the efficacy of amphotericin B (1.5mg/kg/day), voriconazole (60mg/kg/day) and posaconazole (60mg/kg/day) in a murine model of systemic infection caused by Neoscytalidium dimidiatum. All the treatments were able to prolong survival and to reduce the tissue burden in the spleen and kidneys of infected mice. Neither voriconazole nor posaconazole improved the results achieved with amphotericin B.

Topics: Amphotericin B; Animals; Antifungal Agents; Ascomycota; Colony Count, Microbial; Disease Models, Animal; Kidney; Male; Mice; Mycoses; Neutropenia; Pyrimidines; Sepsis; Spleen; Survival Analysis; Treatment Outcome; Triazoles; Voriconazole

Aminocandin (IP960; HMR3270; NXL201) is a new echinocandin with broad-spectrum in vitro activity against Aspergillus and Candida spp. We compared the activity of aminocandin with that of amphotericin B (AmB), itraconazole (ITC) and caspofungin (CAS) in murine models of disseminated aspergillosis against three strains of A. fumigatus, two of which were fully susceptible (AF293 and A1163) and one was resistant to ITC (AF91). Mice were rendered temporarily neutropenic or persistently neutropenic with cyclophosphamide and were infected intravenously 3 days later. Temporarily neutropenic mice were treated with either intraperitoneal (i.p.) AmB (5mg/kg/dose), oral (p.o.) ITC (25mg/kg/dose), intravenous (i.v.) aminocandin (0.25-10mg/kg/dose), i.p. aminocandin (1mg/kg/dose) or solvent control for 9 days. Mice were euthanised 11 days post infection and the kidneys and liver were removed for quantitative culture. Following infection with AF293, only aminocandin 5mg/kg i.v. yielded 100% survival. Aminocandin 1mg/kg i.v., AmB 5mg/kg i.p. or ITC 25mg/kg p.o. were equivalent (P>0.05). Aminocandin 5mg/kg was superior to aminocandin 0.25mg/kg (P<0.0001) as well as all controls (P<0.0001) in reducing mortality. Following infection with AF91, only aminocandin at 5mg/kg and 1mg/kg i.v. yielded 100% survival, which was superior to ITC, aminocandin 0.25mg/kg and controls (all P<0.0001). In the persistently neutropenic model with A1163, aminocandin, CAS and micafungin (2-10mg/kg) were all effective at prolonging survival, with some impact on reducing culture burdens, even with alternate-day dosing (4mg/kg). The only fungicidal regimen was aminocandin 5mg/kg, which sterilised 40% and 50% of mice following infection with AF293 and AF91, respectively. Aminocandin at doses of > or =1mg/kg is highly effective in reducing mortality and organ burden in disseminated infection caused by ITC-susceptible and -resistant A. fumigatus.

Topics: Administration, Oral; Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Caspofungin; Colony Count, Microbial; Disease Models, Animal; Echinocandins; Injections, Intraperitoneal; Injections, Intravenous; Itraconazole; Kidney; Lipopeptides; Liver; Male; Micafungin; Mice; Survival Analysis; Treatment Outcome

We compared the kinetics of amphotericin B (AMB) lung accumulation and fungal clearance by liposomal amphotericin B (L-AMB) and amphotericin B lipid complex (ABLC) in a neutropenic murine model of invasive pulmonary mucormycosis (IPM). Immunosuppressed BALB/c mice were inoculated with 1 x 10(6) Rhizopus oryzae spores and administered L-AMB or ABLC at daily intravenous doses of 1, 5, or 10 mg/kg of body weight for 5 days starting 12 h after infection. At a dose of 10 mg/kg/day, both L-AMB and ABLC were effective at reducing the R. oryzae lung fungal burden and achieved lung tissue concentrations exceeding the isolate mean fungicidal concentration (MFC) of 8 microg/ml by 72 h. When ABLC was dosed at 5 mg/kg/day, the ABLC-treated animals had significantly higher AMB lung concentrations than the L-AMB treated animals at 24 h (6.64 and 1.44 microg/g, respectively; P = 0.013) and 72 h (7.49 and 1.03 microg/g, respectively; P = 0.005), and these higher concentrations were associated with improved fungal clearance, as determined by quantitative real-time PCR (mean conidial equivalent of R. oryzae DNA per lung, 4.44 +/- 0.44 and 6.57 +/- 0.74 log(10), respectively; P < 0.001). Analysis of the AMB tissue concentration-response relationships revealed that the suppression of R. oryzae growth in the lung required tissue concentrations that approached the MFC for the infecting isolate (50% effective concentration, 8.19 microg/g [95% confidence interval, 2.81 to 18.1 microg/g]). The rates of survival were similar in the animals treated with L-AMB and ABLC at 10 mg/kg/day. These data suggest that higher initial doses may be required during L-AMB treatment than during ABLC treatment of experimental IPM.

Topics: Amphotericin B; Animals; Antifungal Agents; Disease Models, Animal; Humans; Lung; Lung Diseases, Fungal; Mice; Mice, Inbred BALB C; Microbial Sensitivity Tests; Mucormycosis; Rhizopus; Treatment Outcome

Cationic antimicrobial peptides have received considerable interest as new therapeutics with the potential for treatment of multiple-drug resistant infections. We recently reported that cholesterol-conjugated G(3)R(6)TAT (CG(3)R(6)TAT) formed cationic nanoparticles via self-assembly, which demonstrated strong antimicrobial activities against various types of microbes in vitro. In this study, the possibility of using these nanoparticles for treatment of Cryptococcus neoformans (yeast)-induced brain infections was studied. The antimicrobial activity of the nanoparticles was tested against 12 clinical isolates of C. neoformans in comparison with conventional antifungal agents amphotericin B and fluconazole. Minimum inhibitory concentrations (MICs) of the nanoparticles were determined to be much lower than those of fluconazole in all the isolates, but slightly higher than those of amphotericin B in some isolates. At a concentration three times higher than the MIC, the nanoparticles completely sterilized C. neoformans after 3.5 h. Cell wall disruption and release of cytoplasmic content were observed under TEM. The biodistribution studies of FITC-loaded nanoparticles in rabbits revealed that the nanoparticles were able to cross the blood-brain barrier (BBB). The efficacy of nanoparticles was further evaluated in a C. neoformans meningitis rabbit model. The nanoparticles crossed the BBB and suppressed the yeast growth in the brain tissues with similar efficiency as amphotericin B did. In addition, unlike amphotericin B, they neither caused significant damage to the liver and kidney functions nor interfered with the balance of electrolytes in the blood. CG(3)R(6)TAT nanoparticles can be a promising antimicrobial agent for treatment of brain infections caused by C. neoformans.

Topics: Amino Acid Sequence; Amphotericin B; Animals; Antifungal Agents; Antimicrobial Cationic Peptides; Colony Count, Microbial; Cryptococcus neoformans; Disease Models, Animal; Fluconazole; Fluorescein-5-isothiocyanate; Meningitis, Cryptococcal; Molecular Sequence Data; Nanoparticles; Rabbits; Tissue Distribution; Treatment Outcome

Protothecosis is an uncommon human infection caused by Prototheca. Prototheca spp can be considered as saprophytes, and in spite of their frequency in the environment, they are of low virulence and may cause chronic infection with low-grade inflammation in humans. At present, only three species are recognized: Prototheca wickerhamii, Prototheca zopfii and Prototheca stagnora. Of these, the former two have been associated with human disease. This study was an investigation of the clinical and microbiological features of a case of granulomatous lymphadenitis due to P. zopfii var. portoricensis in an immunocompetent man in China.. We report the case of a 39-year-old male, who presented with swollen lymph nodes, from which the organism was isolated and identified by the RapidID Yeast Plus test (Remel, Santa Fe, NM, USA) and PCR molecular analysis. The pathogenicity of the isolate was confirmed in a mouse model and antifungal drug susceptibility testing was carried out.. The pathogen was identified as Prototheca zopfii. The DNA sequence of the 18S SSU rDNA regions of the isolate strain were 100% (1205/1205) identical with Prototheca zopfii var. portoricensis. Antifungal susceptibility tests revealed that it was sensitive to amphotericin B, but resistant to 5-flucytosine, fluconazole, ketoconazole, and itraconazole. The patient responded to treatment with intravenous itraconazole and amphotericin B.. Based on the patient's symptoms and microscopic evaluation, cultures, and molecular analyses of the isolate, granulomatous lymphadenitis due to P. zopfii var. portoricensis was diagnosed. P. zopfii var. portoricensis as a causative agent of human lymphadenitis in an immunocompetent case has not been reported, though a few cases of protothecosis have been reported in China. The real number of protothecosis cases may be greater than that reported in the literature. Thus, clinicians should be vigilant for any unknown cause of granulomatous lymphadenitis and should undertake an intensive histopathology, mycology examination, and even molecular analysis to rule out or confirm a potential Prototheca infection.

Topics: Adult; Amphotericin B; Animals; Anti-Infective Agents; Base Sequence; China; Disease Models, Animal; DNA Primers; Humans; Immunocompetence; Itraconazole; Lymphadenitis; Male; Mice; Microbial Sensitivity Tests; Opportunistic Infections; Prototheca

The goal of this study was to compare in vitro and in vivo efficacy of moxifloxacin and liposomal amphotericin B (Amp-B) monotherapies and combination treatment against Candida albicans in an exogenous endophthalmitis model in rabbit eyes. Microplate dilution tests and checkerboard analysis were performed to detect in vitro efficacies. Endophthalmitis was induced by intravitreal injection of C. albicans in 40 rabbit eyes with simultaneous intravitreal drug injection according to prophylactic treatment groups. Group 1 (control group) received 0.1 mL of balanced salt solution, group 2 (moxi group) 100 microg moxifloxacin/0.1 mL, group 3 (Amp-B group) 10 microg liposomal Amp-B/0.1 mL, and group 4 (combi group) both 100 microg moxifloxacin/0.1 mL [DOSAGE ERROR CORRECTED] and 10 microg liposomal Amp-B/0.05 mL intravitreally. Clinical examination, quantitative analysis of microorganisms, and histopathologic examination were performed as in vivo studies. The minimum inhibitory concentration of liposomal Amp-B against C. albicans was found to be 1 microg/mL. Moxifloxacin showed no inhibition of in vitro C. albicans growth. The minimum inhibitory concentration values of liposomal Amp-B for C. albicans were reduced two- to eightfold with increasing concentrations of moxifloxacin in vitro. In vivo, there was no C. albicans growth in the combi group (zero of eight eyes), whereas three eyes (37.5%) showed growth in the Amp-B group. Vitreous inflammation, retinal detachment, focal retinal necrosis, and outer nuclear layer loss were found to be lower in the moxi group compared with the control group. Ganglion cell and inner nuclear layer loss was observed in all eyes (100%) in both the moxi and combi groups, whereas only in 25% (two of eight eyes) in the Amp-B group. Moxifloxacin strongly augments the efficacy of liposomal Amp-B against C. albicans in vitro, although it has no in vitro antifungal activity when used alone. It is interesting that we found a synergistic effect for in vitro tests but failed to demonstrate it in vivo. When 100 microg moxifloxacin/0.1 mL is given intravitreally, it has some toxic effects that are limited to the inner retinal layers.

Topics: Amphotericin B; Animals; Antifungal Agents; Aza Compounds; Candida albicans; Candidiasis; Colony Count, Microbial; Disease Models, Animal; Drug Resistance, Fungal; Drug Therapy, Combination; Endophthalmitis; Eye Diseases; Eye Infections, Bacterial; Eye Infections, Fungal; Fluoroquinolones; Microbial Sensitivity Tests; Moxifloxacin; Quinolines; Rabbits; Vitreous Body

Amphotericin B (AmB) is an antifungal antibiotic the activity of which has been associated with modulation of pro-inflammatory cytokines expression in cultured cells. Herein we reveal that co-administration with AmB enhances the immunogenicity of oral Lip-JENS1 vaccine which derived from liposomes functionalized with DSPC (distearoylphosphatidylcholine) and cholesterol (2:1, molar ratio)-bearing JE virus NS1 protein (600 microg ml(-1)). Oral single dose of Lip-JENS1 elicited a detectable serum NS1-specific IgG antibody response from a mouse model. Remarkably, the addition of AmB (125 microg per mouse), particularly, 2 h prior to, but not simultaneously with, the administration of Lip-JENS1 significantly enhanced the systemic antigen-specific antibody response, providing superior protection against lethal JEV challenges. Further, we observed AmB-induced the transcription of cytokine expression and translocation of transcriptional factor NF-kappaB from the cytoplasm to the nucleus for the murine macrophage J774A.1. Moreover, Peyer's-patch lymphocytes (PPL) from AmB-treated mice produced high levels of IL-1beta, IL-6 and TNF-alpha expression compared to the corresponding control of cells from non-treated mice. Taken together, the results suggest that AmB exerts a profound influence upon mucosal vaccination with Lip-JENS1, possibly playing an adjuvant-augmented role to "fine-tune" humoral as well as cellular immune response, thus conferring enhanced protective immunity for immunising individuals against JE infection.

Topics: Adjuvants, Immunologic; Administration, Oral; Amphotericin B; Animals; Antibodies, Viral; Cell Nucleus; Cytokines; Cytoplasm; Disease Models, Animal; Encephalitis Virus, Japanese; Encephalitis, Japanese; Female; Immunoglobulin G; Japanese Encephalitis Vaccines; Liposomes; Lymphocytes; Macrophages; Mice; Mice, Inbred BALB C; NF-kappa B; Peyer's Patches; Survival Analysis; Viral Nonstructural Proteins

The objective of this study was to investigate the efficacy of liposomal amphotericin B (L-AMB) at a clinical dose (3 mg/kg) against six species (5 genera) of Zygomycetes in a murine lethal infection model, and to compare findings with those for deoxycholate amphotericin B (D-AMB). The correlation between in-vitro activity and in-vivo efficacy of L-AMB was also investigated. Cyclophosphamide-treated mice were inoculated intravenously with conidial suspensions. Four hours or 1 day after inoculation, a single dose of L-AMB or D-AMB was administered intravenously. The number of mice that survived for 14 days was recorded. L-AMB at a dose of at least ≥1 mg/kg significantly prolonged the survival time of infected mice compared with the control group. The ED₅₀ of L-AMB was nearly equivalent to that of D-AMB, except for the treatment initiated on day 1 in the Rhizopus oryzae model. At the maximum tolerated dose (MTD) of each agent, survival percentages with L-AMB (10 mg/kg) were equal to or higher than those with D-AMB (1 mg/kg). The ED₅₀ of L-AMB decreased as the MIC against the infecting strain decreased. In conclusion, L-AMB was effective at a clinical dosage, and at the MTD the efficacy of L-AMB was equal or superior to that of D-AMB in a murine model of disseminated zygomycosis. The in-vivo activity of L-AMB was correlated with its in-vitro activity.

Topics: Amphotericin B; Animals; Antifungal Agents; Deoxycholic Acid; Disease Models, Animal; Drug Combinations; Humans; Male; Mice; Microbial Sensitivity Tests; Mucorales; Mucormycosis; Species Specificity; Survival Rate; Treatment Outcome

Radioimmunotherapy (RIT) prolongs the survival of mice infected with Cryptococcus neoformans. To compare the efficacy of RIT with that of amphotericin B, we infected AJ/Cr mice intravenously with either nonmelanized or melanized C. neoformans cells. Infected mice were either left untreated or treated 24 h after infection with (213)Bi-18B7 antibody, amphotericin B, or both. Melanization before infection did not increase resistance of C. neoformans to RIT in vivo. (213)Bi-18B7 treatment almost completely eliminated colony-forming units from the lung and brain, whereas amphotericin B did not decrease the number of colony-forming units. We conclude that RIT is more effective than amphotericin B against systemic infection with C. neoformans.

Topics: Amphotericin B; Animals; Antibodies, Fungal; Antifungal Agents; Bismuth; Brain; Colony Count, Microbial; Cryptococcosis; Cryptococcus neoformans; Disease Models, Animal; Female; Lung; Mice; Radioimmunotherapy; Radioisotopes; Treatment Outcome

We analysed the in vitro and in vivo effects of posaconazole and amphotericin B against three clinical isolates of zygomycetes: Lichtheimia corymbifera, F1; and Rhizopus oryzae, F5 and F6.. In vitro activities of both drugs were assessed by determining MICs, minimum fungicidal concentrations (MFCs) and fungal damage measured by the XTT assay against either the spores or the hyphal forms. Additionally, the survival curves of neutropenic mice systemically infected with the zygomycete isolates were used as the marker of antifungal response to amphotericin B (1 mg/kg/day) or posaconazole (2.5, 10 and 50 mg/kg/day).. In terms of MICs, posaconazole proved to be active against the three isolates (MICs ranging from 0.125 to 1.0 mg/L). The median posaconazole MFCs were 0.25, 0.5 and >16 mg/L for F1, F5 and F6, respectively. The XTT assay showed that posaconazole was active against spores of all three isolates, but only partially effective against the hyphae. The survival studies showed that amphotericin B at 1 mg/kg/day and posaconazole at 10 mg/kg/day prolonged the survival of the animals infected with L. corymbifera F1. In mice infected with R. oryzae F5, only posaconazole at 50 mg/kg/day significantly prolonged survival, whereas amphotericin B at 1 mg/kg/day was the only regimen active against R. oryzae F6.. Our findings showed that posaconazole could be useful in the treatment of zygomycosis. Also, we report that an isolate of R. oryzae with low MFC responded to posaconazole, while another isolate with high MFC did not.

Topics: Amphotericin B; Animals; Antifungal Agents; Child; Disease Models, Animal; Humans; Male; Mice; Microbial Sensitivity Tests; Microbial Viability; Mucorales; Rhizopus; Survival Analysis; Tetrazolium Salts; Treatment Outcome; Triazoles; Zygomycosis

We previously reported that the IgM MAb B6.1, specific for β-1,2-mannotriose on the surface of the cell wall of Candida albicans, prevents mice from disseminated candidiasis. The preventive activity of the antibody is mediated by enhanced phagocytosis that caused killing of the fungus and involvement of the complement system. In the present study, MAb B6.1 was tested if the antibody enhances therapeutic efficacy of amphotericin B (Amp B) in a murine model of disseminated candidiasis due to C. albicans. Determination by the kidneys-cfu (colony forming unit) and survival times was used to assess treatment. Mice treated intraperitoneally with MAb B6.1 at 1h post-infection with C. albicans (5 x 10⁵ yeast cells/mouse) developed fewer 28%cfu and prolonged survival rates than negative controls, whereas administration of B6.1 to mice at 2h post-infection was ineffective. Therapeutic effect of Amp B on mice with the disseminated disease was dose-dependent, but dosage of Amp B (0.5mg/kg body weight of mice) was not effective. A combination of MAb B6.1 given at 1h post-infection plus Amp B (0.5mg dose) enhanced survival times beyond the effect due to only antibody (P<0.05). The MST (mean survival times) value resulted from the combination therapy-received mice was as almost the same as MST value from 2mg dose of Amp B-given animals (P<0.05). In case mice given a combination of Amp B (0.5mg dose) plus MAb B6.1 at 2h post-infection - a condition of developing no therapeutic efficacy, the combination also reduced disease severity. All these data indicate that MAb B6.1 acts in concert with Amp B, the antibody enhances therapeutic efficacy of Amp B, and this combination therapy augments protection which implies a possibility of reducing Amp B dose. The augmentation of the response appeared to be specific because an irrelevant IgM carbohydrate-specific MAb was not protective. In conclusion, these studies show that Amp B combined with MAb B6.1 may be an option of solving the problem of limited antifungal drug choices due to drug-resistant C. albicans.

Topics: Amphotericin B; Animals; Antibodies, Monoclonal; Antifungal Agents; Candida albicans; Candidiasis, Invasive; Disease Models, Animal; Drug Synergism; Drug Therapy, Combination; Female; Immunoglobulin M; Mice; Mice, Inbred BALB C; Trisaccharides

To develop an oral formulation of amphotericin B (AmB) that is stable at the temperatures of WHO Climatic Zones 3 and 4 (30-43 °C) and to evaluate its efficacy in a murine model of visceral leishmaniasis (VL).. The stability testing of four novel oral lipid AmB formulations composed of mono- and di-glycerides and pegylated esters (iCo-010 to iCo-013) was performed over 60 d and analyzed by HPLC-UV. In addition, the four formulations were incubated 4 h in fasted-state simulated intestinal fluid. AmB concentration was measured spectrophotometrically and emulsion droplet diameter was assessed by dynamic light scattering. Antileishmanial activity of iCo-010 was evaluated at increasing oral doses (2.5 to 10 mg/kg) in a murine model of VL.. AmB stability in the lipid formulation (iCo-010) was >75% over 60 days. After 4 h in fasted-state simulated intestinal fluid, AmB concentration was >95%. iCo-010 demonstrated significant efficacy when orally administered to VL-infected mice bid for five days (inhibition of 99%, 98%, and 83% at 10, 5 and 2.5 mg/kg compared to the vehicle control). In addition, the qd dose of 20 mg/kg provided 96% inhibition compared to the vehicle control.. The oral AmB formulation iCo-010 is stable at the temperatures of WHO Climatic Zones 3 and 4 (30-43 °C). iCo-010 showed excellent antileishmanial activity at both 10 mg/kg po bid for 5 days (<99% reduction in parasitic infection) and 20 mg/kg po qd for 5 days (95% inhibition when compared to control).

Topics: Administration, Oral; Amphotericin B; Animals; Antiprotozoal Agents; Chromatography, High Pressure Liquid; Disease Models, Animal; Drug Stability; Leishmaniasis, Visceral; Mice; Mice, Inbred BALB C; Temperature; Time Factors; Treatment Outcome

A new potent antiinfective and antiparasitic 2,3-dihydro-1H-indolizinium chloride (1) was isolated from Prosopis glandulosa var. glandulosa. Three additional new (2-4) and one known (5) indolizidines were also isolated, and the dihydrochloride salts of 1-3 (compounds 6, 7, and 8) were prepared. Structures were determined by 1D and 2D NMR and mass spectra. Compound 1 showed potent in vitro antifungal activity against Cryptococcus neoformans and Aspergillus fumigatus (IC(50) values = 0.4 and 3.0 microg/mL, respectively) and antibacterial activity against methicillin-resistant Staphylococcus aureus and Mycobacterium intracellulare (IC(50) values of 0.35 and 0.9 microg/mL, respectively). The remarkable in vitro fungicidal activity of 1-4 against C. neoformans (MFCs = 0.63-1.25 microg/mL) and 2, 3, and 5 against A. fumigatus (MFCs = 0.63-2.5 microg/mL) were similar to amphotericin B, but >2-4-fold more potent than 6-8. Prosopilosidine (1) showed potent in vivo activity at 0.0625 mg/kg/day/ip for 5 days in a murine model of cryptococcosis by eliminating approximately 76% of C. neoformans infection from brain tissue compared to approximately 83% with amphotericin B at 1.5 mg/kg/day. Compounds 1 and 4 exhibited potent activity and high selectivity index (SI) values against chloroquine-sensitive (D6) and chloroquine-resistant (W2) strains of Plasmodium falciparum, with IC(50) values of 39 and 95 ng/mL and 42 and 120 ng/mL, respectively (chloroquine, IC(50) = 17 and 140 ng/mL). Prosopilosine (1) also showed in vivo antimalarial activity, with an ED(50) value of approximately 2 mg/kg/day/ip against Plasmodium berghei-infected mice after 3 days of treatment.

Topics: Animals; Anti-Infective Agents; Antiparasitic Agents; Aspergillus fumigatus; Brain; Candida albicans; Chloroquine; Cryptococcus neoformans; Disease Models, Animal; Drug Screening Assays, Antitumor; Humans; Indolizidines; Inhibitory Concentration 50; Methicillin-Resistant Staphylococcus aureus; Mice; Microbial Sensitivity Tests; Molecular Structure; Nevada; Plants, Medicinal; Plasmodium berghei; Prosopis

Experience with anidulafungin against Candida krusei is limited. Immunosuppressed mice were injected with 1.3 x 10(7) to 1.5 x 10(7) CFU of C. krusei. Animals were treated with saline, 40 mg/kg fluconazole, 1 mg/kg amphotericin B, or 10 and 20 mg/kg anidulafungin for 5 days. Anidulafungin improved survival and significantly reduced the number of CFU/g in kidneys and serum beta-glucan levels.

Topics: Anidulafungin; Animals; Antifungal Agents; beta-Glucans; Candida; Candidiasis; Disease Models, Animal; Echinocandins; Kidney; Male; Mice

We tested ten day courses of amphotericin B (AMB), micafungin (MFG), voriconazole (VRC), flucytosine (5FC) and posaconazole (PSC) alone and in double or triple combinations in the treatment of disseminated infections caused by Cladophialophora bantiana in a murine model. Animals were monitored for survival for 40 days. We found that PSC at 100 mg/kg or 5FC at 180 mg/kg prolonged survival over controls. The combinations PSC+MFG and PSC+5FC improved survival compared to MFG and 5FC alone, but were not superior to PSC alone. The triple combination of PSC+MFG+5FC improved the survival with respect to both the control group and the component monotherapies, but all the animals died during the experiment. When treatment with this triple therapy was extended up to 30 days, half of the animals survived for at least 10 months. Combination therapy with the three drugs (PSC, MFG and 5FC) appears to be a promising option for the treatment of C. bantiana infections.

Topics: Amphotericin B; Animals; Antifungal Agents; Ascomycota; Disease Models, Animal; Drug Therapy, Combination; Echinocandins; Flucytosine; Humans; Lipopeptides; Male; Micafungin; Mice; Mycoses; Treatment Outcome; Triazoles

We assessed the in vitro antimicrobial activity and the in vivo efficacy of dipping ventricular assist devices in a combination of N-acetylcysteine, gentamicin, and amphotericin B (NAC/G/A). Ventricular assist devices dipped in NAC/G/A exhibited broad-spectrum antimicrobial activity in vitro and were less likely than undipped devices to become colonized with Staphylococcus aureus in a rabbit model.

Topics: Acetylcysteine; Amphotericin B; Animals; Anti-Bacterial Agents; Coated Materials, Biocompatible; Disease Models, Animal; Equipment Contamination; Gentamicins; Heart-Assist Devices; Humans; Prosthesis-Related Infections; Rabbits; Staphylococcal Infections; Staphylococcus aureus

No clinical studies have compared the efficacy of liposomal formulation AMB (L-AMB) and voriconazole (VRC) in the treatment of pulmonary aspergillosis. The aim of this study was to compare the efficacy of L-AMB and VRC in murine pulmonary aspergillosis.. Leucopenic mice were infected intratracheally with Aspergillus fumigatus and treated intravenously with L-AMB (once a day) or VRC (twice a day).. L-AMB and VRC at a dose of >or=5 and >or=20 mg/kg, respectively, significantly prolonged the survival time of infected mice and reduced the pulmonary fungal burden in comparison with the control group. At the maximum recommended dose for clinical use, 5 mg/kg of L-AMB exhibited greater efficacy than 10 mg/kg of VRC, which achieved an area under the concentration-time curve level equivalent to that of 6 mg/kg (loading dose) in humans, in terms of increasing survival and reducing the fungal burden.. The in vivo efficacy of L-AMB was superior to that of VRC at the maximum recommended dose in a murine pulmonary aspergillosis model.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillus fumigatus; Disease Models, Animal; Lung; Male; Mice; Pulmonary Aspergillosis; Pyrimidines; Triazoles; Voriconazole

New lipid-associated formulations of amphotericin B (AmB) have been developed in order to reduce toxicity and enhance the efficacy of AmB by allowing administration of higher doses of the drug. We determined the in vivo dose-response relationships of 1 day and 7 day treatment of AmB, Ambisome (AmBi) and Abelcet (ABLC) in a non-neutropenic murine model of invasive aspergillosis by using survival as an endpoint. Female CD-1 mice were infected intravenously 48 h prior to start therapy with Aspergillus fumigatus (1 x 10(7) conidia/mouse). Groups of 10 mice were treated iv for 1 day or 7 days with increasing 2-fold doses of AmB, ABLC and AmBi up to a maximum of 20 mg/kg/day. Mortality was determined twice daily until day 15. Results were analyzed using product-moment survival analysis and by determining the dose response relationships on day 15. Survival at day 15 of mice with 7 day AmBi or ABLC treatment was significantly better than that of controls or AmB. The ED50s of AmBi and ABLC were 0.06 (95% CI: 0.03-0.127) mg/kg and 0.21 (0.06-0.66) mg/kg respectively. In addition, the maximum effect was higher for AmBi than ABLC, 90% survival versus 68%, respectively. Most of the effects of treatment with AmBi were reached after 1 day of treatment, indicating that the first dose given is most important in predicting survival. This study shows that AmBi and ABLC were significantly more efficacious than AmB in a non-neutropenic murine model of invasive aspergillosis, and that the effect observed was primarily dependent on the first dose administered.

Topics: Amphotericin B; Animals; Aspergillosis; Aspergillus fumigatus; Disease Models, Animal; Dose-Response Relationship, Drug; Female; Mice; Neutropenia; Nonlinear Dynamics; Survival Analysis

To examine the clinical pathology and management of Paecilomyces lilacinus keratitis.. Observational case series, literature review, and laboratory study.. Characteristics and outcome of 17 patients with laboratory-confirmed Paecilomyces keratitis treated at 2 referral centers were combined with 25 previously reported cases. Experimental models were developed by topically inoculating a human corneal isolate of P. lilacinus onto murine eyes and onto human donor corneas.. Of 42 reported eyes with Paecilomyces keratitis, 13 (31%) were associated with chronic keratopathy or previous ocular surgery, 11 (26%) followed corneal trauma, and 10 (24%) occurred in soft contact lens wearers. Medical cure occurred in 13 (31%), including 9 of 31 eyes (29%) treated with natamycin or amphotericin B. Penetrating keratoplasty or other surgery was performed in 29 (69%). In vitro testing of P. lilacinus indicated resistance to natamycin and amphotericin B but susceptibility to ketoconazole and voriconazole. Experimental inoculation after superficial scarification established moderately severe corneal paecilomycosis by hyphae and conidia in immunosuppressed mice and in explanted donor corneas.. P. lilacinus is an emerging fungal pathogen that infects corneal tissue by filamentous invasion with occasional intrastromal sporulation. P. lilacinus keratitis does not reliably respond to natamycin or amphotericin B and has often required therapeutic keratoplasty, but topical azole antifungal agents such as voriconazole appear promising.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Amphotericin B; Animals; Anti-Bacterial Agents; Combined Modality Therapy; Cornea; Corneal Ulcer; Disease Models, Animal; Eye Infections, Fungal; Female; Humans; Keratoplasty, Penetrating; Male; Mice; Mice, Inbred BALB C; Microbial Sensitivity Tests; Middle Aged; Mycoses; Natamycin; Paecilomyces; Tissue Donors; Treatment Outcome

We have evaluated the efficacies of micafungin, amphotericin B, and voriconazole, alone and in double and triple combinations, in a murine model of systemic infection by Scedosporium prolificans. Micafungin combined with voriconazole or amphotericin B was the most effective, these being the only treatments able to prolong survival and to reduce the fungal load in the kidneys and brain. Triple combinations of these drugs did not improve the results obtained with double combinations.

Topics: Amphotericin B; Animals; Antifungal Agents; Brain; Disease Models, Animal; Drug Resistance, Fungal; Drug Therapy, Combination; Echinocandins; Humans; Kidney; Lipopeptides; Male; Micafungin; Mice; Microbial Sensitivity Tests; Mycetoma; Pyrimidines; Scedosporium; Treatment Outcome; Triazoles; Voriconazole

In separate previous studies, we have shown that lipid-complexed amphotericin B (Abelcet [ABLC]) and liposomal amphotericin B (AmBisome [AmBi]) are efficacious against coccidioidal meningitis in rabbits. Here, we compared ABLC and AmBi directly in a coccidioidal meningitis model. Male New Zealand White rabbits were infected with 5 x 10(4) Coccidioides posadasii arthroconidia by direct cisternal puncture. Therapy with intravenous ABLC or AmBi at 7.5 or 15 mg/kg of body weight or sterile 5% dextrose water (D5W) began 5 days later. Clinical assessments were done daily; cerebrospinal fluid and blood samples were obtained on day 15 and upon euthanasia. Survivors to day 25 were euthanatized, the numbers of CFU in their tissues were determined, and histology analyses of the brains and spinal cords were done. Controls showed progressive disease, whereas animals treated with either dose of either drug showed few clinical signs of infection. All ABLC- or AmBi-treated rabbits survived, whereas eight of nine D5W-treated rabbits were euthanatized before day 25 (P < 0.0001). Numbers of CFU in the brains and spinal cords of ABLC- or AmBi-treated animals were 100- to 10,000-fold lower than those in the corresponding tissues of D5W-treated animals (P < 0.0006 to 0.0001). However, only two or fewer given a regimen of ABLC or AmBi were cured of infection in both tissues. Fewer ABLC-treated rabbits (four of eight treated with 7.5 mg/kg and five of eight treated with 15 mg/kg) than controls (nine of nine) had meningitis at any level of severity (P, 0.015 or 0.043 for animals treated with ABLC at 7.5 or 15 mg/kg, respectively). Although groups of rabbits treated with AmBi regimens did not have significantly fewer animals with meningitis than the control group (P > 0.05), ABLC and AmBi were not significantly different. In this model, intravenous ABLC and AmBi were similarly highly effective, with few clinical signs of infection, 100% survival, and significantly reduced fungal burdens among treated animals. There appeared to be little benefit in using the 15-mg/kg dosage of either formulation. There was no significant advantage of one drug over the other for this indication. Further studies are required to determine the lowest effective doses of these formulations.

Topics: Amphotericin B; Animals; Antifungal Agents; Brain; Cerebrospinal Fluid; Coccidioides; Coccidioidomycosis; Disease Models, Animal; Humans; Male; Meningitis, Fungal; Rabbits; Severity of Illness Index; Spinal Cord; Treatment Outcome

Breakthrough zygomycosis is increasingly observed among patients at high risk for fungal infection who are receiving voriconazole, reflecting either selective pressure or voriconazole-associated alterations in Zygomycetes virulence. We tested the latter hypothesis, using 2 phylogenetically disparate zygomycosis models.. Three Zygomycetes strains were exposed to voriconazole by serial passages on voriconazole-containing medium. The virulence of voriconazole-exposed Zygomycetes strains was compared with that of voriconazole-nonexposed strains in Drosophila and murine models of zygomycosis by assessment of survival curves, pulmonary fungal burdens, and expression of inflammation-associated genes.. Among Toll-deficient (Tl(-/-)) and wild-type fruit flies, infection with Zygomycetes isolates that had been exposed to voriconazole yielded significantly lower survival rates than infection with Zygomycetes strains grown in drug-free media. In contrast, exposure of Rhizopus oryzae to itraconazole, amphotericin B, or caspofungin and exposure of Aspergillus fumigatus to voriconazole did not alter the virulence of these isolates in fruit flies. In the murine model, infection with a R. oryzae strain preexposed to voriconazole was associated with decreased survival rates and increased pulmonary fungal burdens, compared with infection with a voriconazole-nonexposed R. oryzae strain. In addition, enhanced angioinvasion, inflammation, and expression of genes involved in stress response and tissue repair were found in mouse lungs infected with voriconazole-exposed R. oryzae.. Exposure of Zygomycetes organisms to voriconazole selectively enhanced their virulence. The mechanisms underlying these phenotypic changes should be studied further.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillus fumigatus; Disease Models, Animal; Drosophila; Fungi; Humans; Itraconazole; Mice; Mucor; Pyrimidines; Rhizopus; Triazoles; Virulence; Voriconazole; Zygomycosis

We established a murine model of Candida albicans central nervous system (CNS) infection and evaluated the efficacy of anidulafungin. Ten milligrams/kg/day anidulafungin, amphotericin B, or voriconazole significantly reduced mortality and fungal burden in brain tissue, although amphotericin B and 10 mg/kg/day anidulafungin reduced fungal burden in brain tissue to a greater extent than did voriconazole. This suggests a potential role for anidulafungin in the treatment of candidal CNS infection.

Topics: Amphotericin B; Anidulafungin; Animals; Antifungal Agents; Candida albicans; Candidiasis; Central Nervous System Infections; Disease Models, Animal; Echinocandins; Female; Mice; Pyrimidines; Triazoles; Voriconazole

Neutropenic individuals are at high risk for invasive pulmonary aspergillosis (IPA), a life-threatening infection. To evaluate the therapeutic potential of antioxidants, IPA was induced in neutropenic mice and the effect of N-acetyl-l-cysteine (NAC) on oxidative stress levels and lung injury was analyzed.. Mice were pretreated with three daily intraperitoneal injections of 150 mg/kg cyclophosphamide, followed by intratracheal inoculation with 4.5x10(6) conidia of Aspergillus fumigatus. The infected mice were then randomly assigned to an amphotericin B (AMB) group, an AMB plus NAC group, or an untreated control (C) group. In each group, the duration of treatment was 24, 48, or 72 h, and activities such as appearance, feeding, and dermal temperature were observed throughout the experiment. Sera and lung tissues were collected and analyzed by quantitative enzyme-linked immunosorbent assay (ELISA) for total protein, superoxide dismutase (SOD), malondialdehyde (MDA), tumor necrosis factor-alpha (TNF-alpha), and interleukin-10 (IL-10) levels. The wet/dry weight ratio of the lung was also calculated and lung sections were stained with hematoxylin-eosin for pathological examination and with methenamine silver stain for fungus detection.. Compared with the mice untreated with NAC, mice in the AMB plus NAC group had increased SOD and reduced MDA levels both systemically and locally at 24, 48, and 72 h after inoculation with conidia. NAC treatment also decreased the pulmonary protein content at 48 and 72 h and the lung wet/dry weight ratio at 24 and 48 h. Additionally, NAC enhanced pulmonary production of TNF-alpha and IL-10 at 24 h and 48 h.. In combination with antifungal therapy, NAC treatment can alleviate oxidative stress and lung injury associated with IPA in neutropenic mice.Acta Pharmacologica Sinica (2009) 30: 980-986; doi: 10.1038/aps.2009.83.

Topics: Acetylcysteine; Amphotericin B; Animals; Antifungal Agents; Disease Models, Animal; Humans; Interleukin-10; Invasive Pulmonary Aspergillosis; Lung Injury; Male; Mice; Mice, Inbred BALB C; Neutropenia; Oxidative Stress; Random Allocation; Superoxide Dismutase; Tumor Necrosis Factor-alpha

The aim of this study was to evaluate the treatment options of experimental in-vivo Candida endophthalmitis. For inoculation, a 0.1 ml of suspension of Candida albicans was injected into the vitreous of the right eye of each New Zealand rabbit. On the 15th day, the clinical evaluation for the resultant endophthalmitis was noted, and vitreous samples were obtained. On the 21st day, culture positive eyes were divided into four groups in terms of treatment modalities. Group 1 (n = 7) received intravitreal amphotericin B injection, group 2 (n = 8) received both intravitreal dexamethasone and amphotericin B injections, group 3 (n = 8) underwent pars plana vitrectomy (PPV) and amphotericin B injection, and group 4 (n = 8) underwent PPV and both amphotericin B and silicone oil injections. The vitreous samples obtained from right eyes of the rabbits on the 15th day, were all culture positive for Candida albicans. On the 35th day, the least colony counts (colony forming unit) were present in eyes that received only intravitreal amphotericin B injection in group 1, followed by group 4 that underwent PPV and both amphotericin B and silicone oil injections. In Candida endophthalmitis, intravitreal injection of amphotericin B without steroid appears to be the primary choice of therapy. In cases who fail to respond to this regimen alone, PPV in combination with silicone oil injection may be considered. Benefit-risk ratio should be cautiously interpreted for application of intravitreal steroid injection.

Topics: Amphotericin B; Animals; Antifungal Agents; Candida albicans; Candidiasis; Dexamethasone; Disease Models, Animal; Endophthalmitis; Glucocorticoids; Injections, Intraocular; Male; Rabbits; Risk Assessment; Silicone Oils; Vitrectomy; Vitreous Body

SPK-843, a new polyene antifungal, possessed efficacy in a murine model of systemic infection caused by Cryptococcus neoformans. The administration of 4.0 mg/kg SPK-843 led to better survival prolongation and fungal reduction than those observed with the administration of 0.7 mg/kg amphotericin B and 80 mg/kg fluconazole (P < 0.001), without histopathological renal changes.

Topics: Animals; Antifungal Agents; Brain; Cryptococcosis; Cryptococcus neoformans; Disease Models, Animal; Female; Mice; Mice, Inbred BALB C; Polyenes

SPK-843, a new polyene antifungal, exhibited dose-dependent efficacy on murine pulmonary aspergillosis models. SPK-843 doses of higher than 1.0 mg/kg of body weight exhibited no renal toxicities and a tendency toward better survival prolongation than the estimated maximum tolerated doses of amphotericin B (Fungizone) (1.0 mg/kg) and liposomal amphotericin B (AmBisome) (8.0 mg/kg).

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus flavus; Disease Models, Animal; Dose-Response Relationship, Drug; Echinocandins; Lipopeptides; Lipoproteins; Lung Diseases, Fungal; Male; Micafungin; Mice; Polyenes; Treatment Outcome

The manzamines represent a class of marine natural products that show considerable promise in the control of malaria but generate GI distress in rodents when administered orally in high doses. In an effort to generate manzamine prodrugs with improved antimalarial activity and reduced GI toxicity, we prepared acetylated 8-hydroxymanzamine A analogues including 8-acetoxymanzamine A (3) and 8,12-diacetoxymanzamine A (4), and 8-methoxymanzamine A (5) beginning with 8-hydroxymanzamine A (2). The semisynthetic analogues were assayed for antimalarial and antimicrobial activities, cytotoxicity, and biological and chemical stability. Due to gradual hydrolysis of the ester group, application of monoacetate 3 as an antimalarial prodrug was investigated. The in vitro and in vivo bioassays show that acetylated analogues exhibit significant antimalarial activity (IC50( 3) 9.6-30 ng/mL), which are comparable to the parent molecule; however the monoaceate 3 was shown to actually produce higher toxicity at 30 mg/kg when administered orally.

Topics: Administration, Oral; Animals; Antimalarials; Candida albicans; Carbolines; Chlorocebus aethiops; Cryptococcus neoformans; Disease Models, Animal; Inhibitory Concentration 50; Leishmania donovani; Methicillin Resistance; Microbial Sensitivity Tests; Molecular Structure; Plasmodium falciparum; Prodrugs; Vero Cells

In a neutropenic murine model of invasive pulmonary aspergillosis, prophylaxis with single doses of liposomal amphotericin B or micafungin at >or=5 mg/kg of body weight improved animal survival and suppressed the lung fungal burden for up to 7 days after infection, demonstrating the potential utility of infrequent dosing with these antifungals.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillus fumigatus; Colony Count, Microbial; Disease Models, Animal; Drug Administration Schedule; Echinocandins; Female; Invasive Pulmonary Aspergillosis; Lipopeptides; Liposomes; Micafungin; Mice; Mice, Inbred BALB C; Neutropenia

In a murine model of disseminated zygomycosis, low doses of amphotericin B (0.3 mg/kg body weight/day) combined with posaconazole (40 mg/kg/day) prolonged survival and reduced tissue burden with respect to that of controls and that of both drugs administered alone. Results were similar to those obtained with amphotericin B given alone at 0.8 mg/kg/day.

Topics: Amphotericin B; Animals; Antifungal Agents; Colony Count, Microbial; Disease Models, Animal; Drug Synergism; Drug Therapy, Combination; Humans; Male; Mice; Mucormycosis; Rhizopus; Triazoles

The treatment, diagnosis and therapeutic monitoring of hematogenous Candida meningoencephalitis (HCME) are not well understood. We therefore studied the expression of (1-->3)-beta-D-glucan (beta-glucan) in cerebrospinal fluid (CSF) and plasma in a nonneutropenic rabbit model of experimental HCME treated with micafungin and amphotericin B. Groups studied consisted of micafungin (0.5 to 32 mg/kg) and amphotericin B (1 mg/kg) treatment groups and the untreated controls (UC). Despite well-established infection in the cerebrum, cerebellum, choroid, vitreous humor (10(2) to 10(3) CFU/ml), spinal cord, and meninges (10 to 10(2) CFU/g), only 8.1% of UC CSF cultures were positive. By comparison, all 25 UC CSF samples tested for beta-glucan were positive (755 to 7,750 pg/ml) (P < 0.001). The therapeutic response in CNS tissue was site dependent, with significant decreases of the fungal burden in the cerebrum and cerebellum starting at 8 mg/kg, in the meninges at 2 mg/kg, and in the vitreous humor at 4 mg/kg. A dosage of 24 mg/kg was required to achieve a significant effect in the spinal cord and choroid. Clearance of Candida albicans from blood cultures was not predictive of eradication of organisms from the CNS; conversely, beta-glucan levels in CSF were predictive of the therapeutic response. A significant decrease of beta-glucan concentrations in CSF, in comparison to that for UC, started at 0.5 mg/kg (P < 0.001). Levels of plasma beta-glucan were lower than levels in simultaneously obtained CSF (P < 0.05). CSF beta-glucan levels correlated in a dose-dependent pattern with therapeutic responses and with Candida infection in cerebral tissue (r = 0.842). Micafungin demonstrated dose-dependent and site-dependent activity against HCME. CSF beta-glucan may be a useful biomarker for detection and monitoring of therapeutic response in HCME.

Topics: Amphotericin B; Animals; Antifungal Agents; beta-Glucans; Biomarkers; Candidiasis; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Monitoring; Echinocandins; Female; Lipopeptides; Meningitis, Fungal; Meningoencephalitis; Micafungin; Rabbits

In recent years, superficial and deep mycoses caused by trichosporon were occasionally reported. In 2001, we reported the first case of disseminated trichosporonosis caused by Trichosporon asahii (T. asahii) in China. In this study, the pathogenicity of T. asahii was investigated in a murine model of disseminated trichosporonosis.. Seventy-five mice were randomly divided into 7 groups. Each group was inoculated with T. asahii, through intradermal, gastrointestinal tract or intravenous injection. The mice in the experimental groups were given an intraperitoneal injection of cyclophosphamide (CY) to induce granulocytopenia. Mice in the therapeutic group were given both liposomal amphotericin B and fluconazole. The main viscera of the mice were examined by means of tissue culture and pathologic sections.. In the two intravenous inoculation groups, T. asahii was isolated from at least one organ in 10 of the 12 granulocytopenic mice and 2 of the 14 immunocompetent mice. Two of the 7 mice in the granulocytopenia group presented with lesions in the inoculation position, but none of the 30 mice in the granulocytopenia and the control group which were inoculated intradermally or through the gastrointestinal tract had viscera infection. In the therapeutic group, the ratio of consequently dead mice, the number of involved viscera, and the incidence of systemic infection were significantly less than the untreated group. Acute purulent inflammation and granulomatous inflammation were the main pathological changes in the course of the infection. Arthrospores and filaments were found in the focus.. T. asahii is an opportunistic pathogen that causes cutaneous and visceral infections in immunologically impaired hosts. An immunocompetent host was to be infected by the invading T. asahii. Several organs, namely the liver, lungs, kidneys, spleen and heart, were predisposed. The therapy of combining liposomal amphotericin B with fluconazole can prevent the host from an infection and inhibit the diffusion of the infection.

Topics: Amphotericin B; Animals; Antifungal Agents; Cyclophosphamide; Disease Models, Animal; Fluconazole; Male; Mice; Mycoses; Random Allocation; Trichosporon

Effect of antifungal preparation amphotericin B and its lysosomotropic composition with dialdehyde-dextran on functional state of phagocytizing cells in the dynamics of granulomatous inflammation induced by C. albicans was studied on CBA mice. A stimulating effect of amphotericin B on the production of reactive oxygen species by peritoneal and bone marrow phagocytes was observed, while lysosomotropic form of the antibiotic did not stimulate generation of oxygen radicals.

Topics: Amphotericin B; Animals; Antifungal Agents; Candidiasis; Disease Models, Animal; Mice; Phagocytes; Reactive Oxygen Species

To evaluate the efficacy of topical voriconazole in an experimental rabbit model of Fusarium keratitis.. Fungal keratitis was induced in the right eyes of 24 New Zealand rabbits. 8.6 x 10(3) CFU/0.1 ml F.solani spore suspension was injected midstromally into the central cornea. Group 1 received topical amphotericin B 0.15%, group 2 received topical itraconazole 1% and group 3 received topical voriconazole 1% hourly between 08:00 to 22:00 on days 1 and 2; 4 times daily on days 3-5. Control group received topical balanced salt solution at identical intervals. The eyes were examined clinically with a scoring system before treatment (day 0), on day 3 and on day 5. Cultures were taken from the lesion by scraping at the end of the treatment. Clinical scores and microbiologic results were analyzed statistically.. In the control group, keratitis progressed clinically and colony level was 2 x 10(3) CFU at day 5. In all treatment groups, progression of keratitis was inhibited clinically. Culture was sterile in the group receiving amphotericin B. Colony level was 0.3 x 10(2) CFU in the itraconazole group and 2 x 10(2) CFU in the voriconazole group at day 5.. Progression of keratitis was inhibited clinically in all treatment groups. Colony level decreased significantly in all treatment groups. As a result, itraconazole 1% and voriconazole 1% were found to be effective in Fusarium keratitis clinically and microbiologically, although their activity was not as effective as amphotericin B 0.15%.

Topics: Administration, Topical; Amphotericin B; Animals; Antifungal Agents; Colony Count, Microbial; Corneal Ulcer; Disease Models, Animal; Eye Infections, Fungal; Fusarium; Itraconazole; Mycoses; Pyrimidines; Rabbits; Treatment Outcome; Triazoles; Voriconazole

We previously found that caspofungin synergized with amphotericin B lipid complex in treating murine mucormycosis. We now report a similarly enhanced activity of liposomal amphotericin combined with micafungin or anidulafungin in mice with disseminated mucormycosis. The efficacy of combination echinocandin-polyene therapy for mucormycosis is a class effect.

Topics: Amphotericin B; Anidulafungin; Animals; Antifungal Agents; Disease Models, Animal; Drug Therapy, Combination; Echinocandins; Humans; Lipopeptides; Lipoproteins; Liposomes; Male; Micafungin; Mice; Mice, Inbred BALB C; Mucormycosis; Polyenes; Rhizopus; Treatment Outcome

We compared the efficacies of liposomal amphotericin B (LAmB) and an amphotericin B lipid complex (ABLC) in diabetic ketoacidotic (DKA) or neutropenic mice with disseminated zygomycosis. ABLC was as effective as LAmB in neutropenic but not DKA mice. Low-dose ABLC was less effective than LAmB at reducing brain fungal burdens in both models.

Topics: Amphotericin B; Animals; Antifungal Agents; Diabetic Ketoacidosis; Disease Models, Animal; Drug Combinations; Humans; Liposomes; Male; Mice; Mice, Inbred BALB C; Neutropenia; Phosphatidylcholines; Phosphatidylglycerols; Rhizopus; Treatment Outcome; Zygomycosis

In the present study, the purpose is to determine activities of monoamine oxidases (MAO) in the brain of 263K scrapie-infected hamsters during the development of this experimental prion disease. Indeed, MAO activity modifications which have already been related in aging and neurodegenerations is suspected to be involved in the neuron loss process by elevated hydrogen peroxide formation. Monoamine oxidase type A (MAO-A) and B (MAO-B) activities were followed in the brain at different stages of the disease. MAO-A activity did not change significantly during the evolution of the disease. However, concerning the MAO-B activity, a significant increase was observed from 50 days post-infection and through the course of the disease and reached 42.9+/-5.3% at its ultimate stage. Regarding these results, MAO-B could be a potential therapeutic target then we have performed a pre-clinical treatment with irreversible (Selegiline or L-deprenyl) or and reversible (MS-9510) MAO-B inhibitors used alone or in association with an anti-scrapie drug such as MS-8209, an amphotericin B derivative. Our results show that none of the MAO-B inhibitors used was able to delay the onset of the disease. Neither these MAO-B inhibitors nor R-NMDA inhibitors (MK-801) can enhance the effects of MS-8209. The present findings clearly indicate a significant increase of cerebral MAO-B activity in scrapie-infected hamsters. Furthermore, inhibitors of MAO-B do not have any curative or palliative effect on this experimental model indicating that the raise of this activity is probably more a consequence rather than a causal event of the neurodegenerative process.

Topics: Amphotericin B; Animals; Biogenic Monoamines; Brain; Cricetinae; Disease Models, Animal; Dose-Response Relationship, Drug; Female; Mesocricetus; Monoamine Oxidase; Monoamine Oxidase Inhibitors; Nerve Degeneration; PrPSc Proteins; Scrapie

The biological properties of elastase inhibitor from Aspergillus flavus (AFLEI) were investigated. AFLEI was produced at the highest rate when casamino acid was used as the nitrogen source. When a mixture of AFLEI (approx. molecular weight, 7,500) and elastase from A. flavus (approx. molecular weight, 40,000) was detected using anti-AFLEI antibody, molecular weight of the detected mixture was approximately 48,000, indicating that AFLEI and elastase bound at a proportion of 1 : 1. When immunocompromised mice administrered of immunosuppressive (cyclophosphamide) were infected by inhalation of A. flavus and administered amphotericin B (AMB) alone or in combination with AFLEI, survival rate tended to be higher with combination treatment than with AMB alone. Moreover, although extensive bleeding was seen in pathology sections taken from rat lung resected 24 hr after purified elastase was administered to the lung via the bronchus, this bleeding was inhibited by AFLEI. These findings indicate that for the treatment of aspergillosis, combination of an existing antifungal agent with AFLEI can be expected to provide greater therapeutic benefits than administration of an antifungal agent alone.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus flavus; Cyclophosphamide; Disease Models, Animal; Drug Therapy, Combination; Enzyme Inhibitors; Humans; Immunocompromised Host; Mice; Molecular Weight; Pancreatic Elastase; Rats; Virulence

Naegleria fowleri is responsible for producing a rapidly fatal central nervous system infection known as primary amebic meningoencephalitis (PAM). To date, amphotericin B, an antifungal agent, is the only agent with established clinical efficacy in the treatment of PAM. However, amphotericin B is not always successful in treating PAM and is associated with severe adverse effects. We previously found azithromycin to be more effective than amphotericin B in a mouse model of PAM. We therefore investigated the combination of amphotericin B and azithromycin in vitro and in a mouse model of PAM. For the in vitro studies, 50% inhibitory concentrations were calculated for each drug alone and for the drugs in fixed combination ratios of 1:1, 3:1, and 1:3. We found amphotericin B and azithromycin to be synergistic at all three of the fixed combination ratios. In our mouse model of PAM, a combination of amphotericin B (2.5 mg/kg of body weight) and azithromycin (25 mg/kg) protected 100% of the mice, whereas amphotericin B alone (2.5 mg/kg) protected only 27% of mice and azithromycin alone (25 mg/kg) protected 40% of mice. This study indicates that amphotericin B and azithromycin are synergistic against the Lee strain of N. fowleri, suggesting that the combined use of these agents may be beneficial in treating PAM.

Topics: Amphotericin B; Animals; Antifungal Agents; Azithromycin; Central Nervous System Protozoal Infections; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Synergism; Drug Therapy, Combination; Humans; Male; Meningoencephalitis; Mice; Naegleria fowleri; Survival Rate; Treatment Outcome

Three isolates of zygomycetes belonging to two different genera (Rhizopus oryzae and Absidia corymbifera) were used to produce a systemic infection in neutropenic mice. On days -2 and -1 and at 2 h prior to infection, the mice received either posaconazole (POS) at doses ranging from 20 to 80 mg/kg of body weight/day or amphotericin B (AMB) at 1 mg/kg/day. Antifungal drug efficacy was assessed by determination of the prolongation of survival, determination of the percentage of infected organs (brain, lung, spleen, and kidney), and histological examination for the number of infection foci and their sizes in brain and kidney tissues. AMB significantly prolonged the survival of mice infected with all isolates. POS significantly prolonged the survival of mice infected with zygomycetes. Cultured organs from mice infected with R. oryzae were all positive, while treated mice challenged with A. corymbifera generally showed lower percentages of infected organs compared with the percentages for the controls. Zygomycete isolates established an active infection (the presence of hyphae) in the brains and the kidneys of all controls. In mice challenged with R. oryzae, both antifungal drugs were effective at reducing the number and the size of infection foci in the kidneys. Only AMB reduced the numbers, but not the sizes, of infection foci in the brain. Finally, both drugs significantly reduced the numbers and the sizes of infection foci in both tissues of mice infected with A. corymbifera. Our data suggest that prophylaxis with POS has some potential to prevent zygomycosis.

Topics: Absidia; Amphotericin B; Animals; Antibiotic Prophylaxis; Antifungal Agents; Brain; Cells, Cultured; Disease Models, Animal; Kidney; Lung; Male; Mice; Microbial Sensitivity Tests; Mucormycosis; Rhizopus; Spleen; Time Factors; Triazoles

The in vitro and in vivo activities of a series of (2R,3R)-2-(2,4-difluorophenyl)-3-(substituted indazol-1-yl)-1-(1H-1,2,4-triazol-1-yl)butan-2-ol as potential antifungal agents are described. In particular, the analog 12j having 5-bromo substitution on the indazole ring exhibited significant antifungal activity against a variety of fungal cultures (Candida spp. and Aspergillus spp.). In addition, oral administration of 12j showed its excellent efficacy against Candida albicans in a murine infection model and the significantly improved survival rates of the infected mice.

Topics: Administration, Oral; Animals; Antifungal Agents; Aspergillus; Candida; Disease Models, Animal; Indazoles; Mice; Microbial Sensitivity Tests; Rats; Stereoisomerism; Triazoles

In a murine model of blastoschizomycosis, amphotericin B combined with micafungin, flucytosine or voriconazole did not improve the efficacy of fluconazole. However, such combinations can constitute therapeutic options for those cases where fluconazole fails.

Topics: Amphotericin B; Animals; Antifungal Agents; Colony Count, Microbial; Disease Models, Animal; Drug Synergism; Drug Therapy, Combination; Echinocandins; Flucytosine; Geotrichosis; Geotrichum; Humans; Immunocompromised Host; Lipopeptides; Lipoproteins; Male; Micafungin; Mice; Mice, Inbred Strains; Microbial Sensitivity Tests; Mycoses; Peptides, Cyclic; Pyrimidines; Survival Analysis; Triazoles; Trichosporon; Voriconazole

We developed a guinea pig model of cryptococcal meningitis to evaluate antifungal agents. Immunosuppressed animals challenged intracranially with Cryptococcus neoformans responded to fluconazole and voriconazole. Disease was monitored by serial cerebrospinal fluid (CSF) cultures and quantitative organ cultures. Our model produces disseminating central nervous system disease and responds to antifungal therapy.

Topics: Animals; Antifungal Agents; Cerebrospinal Fluid; Colony Count, Microbial; Cryptococcus neoformans; Disease Models, Animal; Fluconazole; Guinea Pigs; Humans; Male; Meningitis, Cryptococcal; Pyrimidines; Triazoles; Voriconazole

The purpose of this study was to assess the antifungal activity, pharmacokinetics, and tissue distribution of amphotericin B (AmpB) following the administration of Abelcet and AmBisome alone and in combination with Caspofungin to rats infected with Aspergillus fumigatus. Aspergillus fumigatus inoculum (2.1-2.5 x 10(7) colony forming units [CFU]) was injected via the jugular vein; 48 h later male albino Sprague-Dawley rats (350-400 g) were administered either a single intravenous (i.v.) dose of Abelcet (5 mg AmpB/kg; n = 6), AmBisome (5 mg AmpB/kg; n = 6), Caspofungin (3 mg/kg; n = 5), Abelcet (5 mg AmpB/kg) plus Caspofungin (3 mg/kg) (n = 6), AmBisome (5 mg AmpB/kg) plus Caspofungin (3 mg/kg) (n = 7), or physiologic saline (non-treated controls; n = 6) once daily for 4 days. Antifungal activity was assessed by organ CFU concentrations and plasma galactomannan levels. Plasma and tissue samples were taken from each animal for AmpB pharmacokinetic analysis and tissue distribution determinations. Abelcet treatment significantly decreased total fungal CFU concentrations recovered in all the organs added together by 73% compared to non-treated controls. Ambisome treatment significantly decreased total fungal CFU concentrations recovered in all the organs added together by 69% compared to non-treated controls. Caspofungin treatment significantly decreased total fungal CFU concentrations recovered in all the organs added together by 80% compared to non-treated controls. Abelcet plus Caspofungin treatment significantly decreased total fungal CFU concentrations recovered in all the organs added together by 81% compared to non-treated controls. Ambisome plus Caspofungin treatment significantly decreased total fungal CFU concentrations recovered in all the organs added together by 98% compared to non-treated controls. Abelcet treatment significantly decreased plasma galactomannan levels by 50 and 75% 96 h following the initiation of treatment in the absence and presence of Caspofungin co-therapy, respectively. AmBisome treatment significantly decreased plasma galactomannan levels by 73 and 78% 96 h following the initiation of treatment in the absence and presence of Caspofungin co-therapy, respectively. Co-administration of Caspofungin with Abelcet and AmBisome did not significantly alter the plasma concentration-time profile, pharmacokinetic parameters, and tissue distribution of AmpB. Taken together, our findings suggest that an alternative mechanism, possibly at t

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Caspofungin; Colony Count, Microbial; Disease Models, Animal; Drug Administration Schedule; Drug Combinations; Drug Therapy, Combination; Echinocandins; Galactose; Injections, Intravenous; Lipopeptides; Male; Mannans; Peptides, Cyclic; Phosphatidylcholines; Phosphatidylglycerols; Rats; Rats, Sprague-Dawley; Tissue Distribution

Disseminated candidiasis is associated with a high rate of morbidity and mortality. The presence of neutrophils and the timely administration of antifungal agents are likely to be critical factors for a favorable therapeutic outcome of this syndrome. The effect of neutropenia on the temporal profile of the burden of Candida albicans in untreated mice and those treated with amphotericin B was determined using a pharmacodynamic model of disseminated candidiasis. A mathematical model was developed to describe the rate and extent of the C. albicans killing attributable to neutrophils and to amphotericin B. The consequences of a delay in the administration of amphotericin B, flucytosine, or micafungin were studied by defining dose-response relationships. Neutrophils caused a logarithmic decline in fungal burden in treated and untreated mice. The combination of amphotericin B and neutrophils resulted in a high rate of Candida killing and a sustained anti-C. albicans effect. In neutropenic mice, 5 mg/kg of body weight of amphotericin B was required to prevent progressive logarithmic growth. An increased delay in drug administration resulted in a reduction in the maximum effect to a point at which no drug effect could be observed. Neutrophils and the timely initiation of antifungal agents are critical determinants in the treatment of experimental disseminated candidiasis.

Topics: Amphotericin B; Animals; Antifungal Agents; Candida albicans; Candidiasis; Disease Models, Animal; Dose-Response Relationship, Drug; Echinocandins; Flucytosine; Kidney; Lipopeptides; Lipoproteins; Male; Micafungin; Mice; Microbial Sensitivity Tests; Neutropenia; Neutrophils; Peptides, Cyclic; Time Factors

Blastoschizomyces capitatus is an emerging pathogenic fungus that can cause deep invasive diseases in neutropenic patients. We developed a model of disseminated blastoschizomycosis in immunosuppressed mice to evaluate the effectiveness of amphotericin B, flucytosine, fluconazole and voriconazole. High-dose fluconazole was the most effective drug at prolonging the survival of mice and at reducing fungal burden in the kidneys, spleen and liver.

Topics: Amphotericin B; Animals; Antifungal Agents; Disease Models, Animal; Dose-Response Relationship, Drug; Fluconazole; Flucytosine; Geotrichosis; Geotrichum; Immunocompromised Host; Immunosuppressive Agents; Kidney; Liver; Male; Mice; Microbial Sensitivity Tests; Pyrimidines; Spleen; Survival Analysis; Treatment Outcome; Triazoles; Voriconazole

Neutropenic mice with latent trichosporonemia were given various antifungal agents (amphotericin B, fluconazole, itraconazole) or saline to determine which antifungal agent could be useful for prophylaxis. The 3-week-survival rate was 80% in the fluconazole group, 50% in the amphotericin B group, 45% in the itraconazole group, and 30% in the saline group. Compared with the other antifungal agents, fluconazole offered superior prophylaxis against the progression of trichosporonosis fungemia to disseminated disease (P<0.05). These results suggest that clinical studies are warranted to investigate fluconazole prophylaxis of trichosporonosis progression in neutropenic patients, such as people receiving chemotherapy and patients who have received solid organ transplants.

Topics: Amphotericin B; Animal Structures; Animals; Antibiotic Prophylaxis; Antifungal Agents; Cyclophosphamide; Disease Models, Animal; Fluconazole; Fungemia; Itraconazole; Male; Mice; Mice, Inbred ICR; Microbial Sensitivity Tests; Neutropenia; Survival Analysis; Treatment Outcome; Trichosporon

The reformulation of amphotericin B (AMB) into a lipid complex (AMB lipid complex [ABLC]) or liposomal carrier (liposomal AMB [L-AMB]) changes the rate and extent of drug distribution to the lung. The importance of pharmacokinetic differences among the various lipid AMB formulations in the treatment of invasive pulmonary aspergillosis (IPA) remains unknown. We compared the kinetics of AMB lung accumulation and fungal clearance of ABLC- and L-AMB-treated mice with acute IPA. BALB/c mice were immunosuppressed with cyclophosphamide and cortisone before intranasal inoculation with 1.5x10(6) Aspergillus fumigatus 293 conidia. ABLC or L-AMB was administered in daily intravenous doses (1, 5, or 10 mg/kg of body weight), starting 12 h after infection and continuing until day 5. At predetermined times (0, 24, 72, and 120 h), mice were euthanized, and lungs were harvested for determinations of lung fungal burdens (quantitative PCR) and total AMB lung tissue concentrations. Both ABLC and L-AMB were effective at reducing lung fungal burdens at doses of >or=5 mg/kg/day. Clearance of A. fumigatus during the first 24 h was associated with AMB tissue concentrations of >4 microg/g. At 5 mg/kg/day, ABLC produced a more rapid fungal clearance than did L-AMB, but at the end of therapy, fungal burden reductions were similar for both formulations and were not improved with higher dosages. These data suggest that ABLC delivers active AMB to the lung more rapidly than does L-AMB, resulting in faster Aspergillus clearance in an experimental model of IPA. However, pharmacodynamic differences between the two formulations were less apparent when mice were dosed at 10 mg/kg/day.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Disease Models, Animal; Lipids; Liposomes; Lung Diseases, Fungal; Mice; Mice, Inbred BALB C

To evaluate the efficacy of newly developed antifungal agents caspofungin and voriconazole in Candida albicans endophthalmitis in rabbit eyes.. Thirty New Zealand white rabbits were divided into four treatment groups and one control group. One eye of each rabbit was infected by inoculation of 1 x 10(4) CFU/ml of C. albicans. Seventy-two hours after the inoculation, caspofungin 100 microg/0.1 ml in group 1 (n = 6), voriconazole 50 microg/0.1 ml in group 2 (n = 6), amphotericin B 10 microg/0.1 ml in group 3 (n = 6), itraconazole 10 microg/0.1 ml in group 4 (n = 6), and 0.1 ml NaCl 0.9% in control group (n = 6) were injected into the vitreous cavity. Clinical and histopathologic examination scores and microbiological analysis of vitreous aspirates were compared.. There was statistically significant difference in the clinical scores, histopathologic scores, and mean CFU/ml between the treatment and control groups (p < 0.05). In caspofungin and voriconazole groups, histopathologic scores and mean CFU were lower than other treatment groups and control group.. Intravitreal injection of caspofungin and voriconazole was effective against C. albicans endophthalmitis in this experimental rabbit model.

Topics: Amphotericin B; Animals; Antifungal Agents; Candida albicans; Candidiasis; Caspofungin; Colony Count, Microbial; Cornea; Disease Models, Animal; Echinocandins; Endophthalmitis; Eye Infections, Fungal; Itraconazole; Lipopeptides; Peptides, Cyclic; Pyrimidines; Rabbits; Triazoles; Voriconazole

To evaluate the efficacy of caspofungin in an experimental rabbit model of Fusarium keratitis and to compare it with amphotericin B.. Eighteen New Zealand white rabbits were randomly divided into 2 treatment groups and 1 control group. One cornea of each rabbit was inoculated with Fusarium solani spores. The first group received topical amphotericin B 0.15%, the second group received topical caspofungin 1%, and the control group received topical balanced salt solution hourly for 2 days and then 4 times daily for 3 additional days. Treatment effects were evaluated by clinical assessment at days 3 and 5 and by fungal culture after 5 days of treatment.. In the treatment groups, progression of keratitis was inhibited, and cultures were sterile at the end of the study. In the control group, keratitis progressed, and cultures were positive for F. solani.. Topical caspofungin is effective in Fusarium keratitis, and clinical efficacy studies seem justified.

Topics: Administration, Topical; Amphotericin B; Animals; Antifungal Agents; Caspofungin; Corneal Ulcer; Disease Models, Animal; Echinocandins; Eye Infections, Fungal; Fusarium; Lipopeptides; Mycoses; Peptides, Cyclic; Rabbits; Treatment Outcome

Amphotericin B (AmB) was formulated in trilaurin-based emulsomes (nanosize lipid particles) stabilized by soya phosphatidylcholine (PC), as a new delivery system for macrophage targeting for the treatment of visceral leishmaniasis (VL). Emulsomes were modified by coating them with macrophage-specific ligand (O-palmitoyl mannan, OPM). The antileishmanial activity of AmB-deoxycholate (AmB-Doc) and emulsome entrapped AmB was tested in vitro in Leishmania donovani infected macrophage-amastigote system (J774A.1 cells), which showed higher efficacy of OPM grafted AmB emulsomes (TLEs-OPM) over plain AmB emulsomes (TLEs) and AmB-Doc. The in vivo antileishmanial activity of the AmB (0.5 mg/kg) was tested in AmB-Doc, TLEs and TLEs-OPM forms against VL in L. donovani infected hamsters. Formulation TLEs-OPM eliminated intracellular amastigotes of L. donovani within splenic macrophages more efficiently (73.7 +/- 6.7% parasite inhibition) than the formulation TLEs (51.7 +/- 5.4% parasite inhibition) (P < 0.01) or AmB-Doc (30.4 +/- 4.8% parasite inhibition) (P < 0.001). Our results suggest that these newer formulations (plain and ligand appended emulsomes) are a promising alternative to the conventional AmB-Doc formulation for the treatment of VL.

Topics: Amphotericin B; Animals; Cricetinae; Deoxycholic Acid; Disease Models, Animal; Drug Carriers; Drug Combinations; Leishmania donovani; Leishmaniasis, Visceral; Macrophages; Male; Mesocricetus; Mice; Nanoparticles; Trypanocidal Agents

Disseminated phaeohyphomycosis is an uncommon infection affecting immunocompetent and immunocompromised individuals in which response to older antifungal agents has been variable. We compared the effect of six days of therapy with caspofungin, posaconazole, and amphotericin B in parallel studies of survival and fungal burden in an immunocompromised mouse model of Exophiala infection. Mice immunocompromised with cyclophosphamide were treated for 6 days starting one day after initiation of infection. Treatment regimens included amphotericin B, caspofungin, and posaconazole. In the survival studies, experimental animals were observed for 14 days. In the fungal burden tests the experimental animals were sacrificed 7 days after infection and brain and kidney burden determined. Treatment with any agent decreased mortality (P < 0.05), with 40%, 30%, and 80% observed survival of the animals treated with amphotericin B, caspofungin, and posaconazole, respectively. Amphotericin B and posaconazole treatment resulted in a decrease in fungal burden compared to untreated controls (P < 0.05). No reduction in fungal burden was noted in the caspofungin group. All three antifungals evaluated improved survival of immunocompromised mice in this otherwise fatal disseminated phaeohyphomycosis. Amphotericin B and posaconazole reduced fungal burden. Posaconazole and caspofungin appear to have potential for use in treatment of this rare infection.

Topics: Amphotericin B; Animals; Antifungal Agents; Brain; Caspofungin; Disease Models, Animal; Echinocandins; Exophiala; Female; Immunocompromised Host; Kidney; Lipopeptides; Mice; Mice, Inbred ICR; Mycoses; Survival Analysis; Triazoles

The aim of this study was to compare the pharmacodynamics of the azole antifungal drugs fluconazole, itraconazole and ketoconazole, and the polyene antifungal amphotericin B, in a mouse model of disseminated Candida albicans infection. In order to directly compare effective serum concentrations of these antifungals, drug concentrations were assayed microbiologically by measuring inhibition of C. albicans mycelial growth (mMIC) in a mouse serum-based assay (serum antifungal titer). Efficacy in the mouse infection model was determined using an organ-based (kidney burden) endpoint. For all four drugs, the serum antifungal titers, 8 hr after administration of single doses of drugs at a range of drug concentrations, correlated closely with C. albicans kidney fungal burden in the mouse model. The results showed that determining serum antifungal titer may be used to accurately represent kidney fungal burden in a mouse model of disseminated candidiasis and allowed direct comparison of the pharmacodynamics of differing classes of antifungal drugs.

Topics: Amphotericin B; Animals; Antifungal Agents; Candida albicans; Candidiasis; Disease Models, Animal; Fluconazole; Itraconazole; Kidney; Mice; Microbial Sensitivity Tests

Lysosomotropic composition of dialdehyde dextran and amphotericin B had a greater therapeutic effect in mice with systemic candidiasis compared to free amphotericin B. This composition normalized glucocorticoid function of the adrenal glands and decreased the severity of liver destruction at late terms of granulomatous inflammation.

Topics: Amphotericin B; Animals; Antifungal Agents; Candida albicans; Candidiasis; Dextrans; Disease Models, Animal; Drug Therapy, Combination; Granuloma; Liver Diseases; Male; Mice; Mice, Inbred C57BL

Whether or not flucytosine should be administered to patients infected with Cryptococcus neoformans isolates found to be resistant to flucytosine in vitro remains a controversial issue. Thus, the efficacy of amphotericin B and flucytosine in combination was investigated by mortality and fungal burden studies in a murine model of disseminated cryptococcosis using two clinical isolates of Cryptococcus neoformans, one susceptible and one resistant (i.e., 64 microg/ml) to flucytosine. Amphotericin B was given intraperitoneally at 0.25 or 0.5 mg/kg/day, while flucytosine was given at 100 or 250 mg/kg/day orally. Treatment was started 24 h or day 6 after inoculation and continued for 5 days in fungal burden and mortality studies, respectively. The combination of amphotericin B at 0.5 mg/kg/day and flucytosine at 250 mg/kg/day was significantly more effective than monotherapies for reducing fungal burden in brain, spleen, and lungs after infection by the flucytosine-susceptible isolate and in brain and spleen for the flucytosine-resistant isolate. For the flucytosine-resistant isolate, the combination of amphotericin B at 0.5 mg/kg/day with flucytosine at 100 mg/kg/day was significantly better than monotherapies for reducing the fungal burden in the brain. Survival obtained after the combination of amphotericin B at 0.5 mg/kg/day and flucytosine at 250 mg/kg/day increased compared to that obtained with monotherapies for both isolates, but the difference was statistically significant only for the flucytosine-susceptible isolate. Antagonism was never observed. This study demonstrates the beneficial effect of the addition of flucytosine to amphotericin B against experimental disseminated cryptococcal infection even when the C. neoformans isolate is resistant to flucytosine.

Topics: Amphotericin B; Animals; Antifungal Agents; Brain; Cryptococcosis; Cryptococcus neoformans; Disease Models, Animal; Drug Combinations; Drug Therapy, Combination; Flucytosine; Lung

It is generally accepted that the lipid formulations of amphotericin B (AMB) are not as potent as conventional AMB on a milligram-per-kilogram basis. We used a neutropenic murine disseminated candidiasis model to compare the in vivo potencies of AMB, liposomal AMB (L-AMB), and AMB lipid complex (ABLC) pharmacodynamically. The pharmacokinetics of the antifungals were examined in serum and in three organs commonly seeded in disseminated candidiasis (kidneys, liver, and lung). Both single-dose time-kill studies and multiple-dosing-regimen studies were used with each of the compounds. Determinations of the numbers of CFU in the kidneys were performed following the administration of three escalating single doses of the polyenes at various times over 48 h. The areas under the time-kill curves (AUTKs) for each dose level of the drugs were compared by analysis of variance (ANOVA). In the multiple-dosing-regimen studies with five Candida isolates, AMB, L-AMB, and ABLC were administered daily for 72 h. The organism burdens in the mouse kidneys were similarly used as the treatment end point. Additional multiple regimen-dosing-studies were performed with a single Candida albicans isolate, and the microbiologic outcomes in four internal organs (kidneys, liver, spleen, and lung) were examined at the end of therapy (48 h). The relationship between the dose and the drug exposure expressed by the pharmacokinetics of the dosing regimens in serum and organ tissue were analyzed by using a maximum-effect model. ANOVA was used to compare the drug exposures necessary to achieve the 25% effective dose (ED25), ED50, ED75, and 1 log10 killing. Comparison of AUTKs suggested that AMB was 4.3- to 5.9-fold more potent than either ABLC or L-AMB. The time-kill curves for both lipid formulations were very similar. In the multiple-dosing-regimen studies, AMB was 5.0- to 8.0-fold more potent than each of the lipid formulations against five Candida isolates in the kidneys. Similar differences in potency (5.1- to 7.2-fold) were observed in the other end organs. The difference in pharmacokinetics in serum accounted for much of the difference in potency between AMB and ABLC (ratio of serum ABLC area under the curve of effective doses to serum AMB area under the curve of effective doses, 1.2). The differences in the kinetics in the various end organs between AMB and L-AMB were better at explaining the disparate potencies at these infection sites (ratio of organ L-AMB area under the curve of eff

Topics: Amphotericin B; Animals; Antifungal Agents; Area Under Curve; Candida; Candidiasis; Disease Models, Animal; Female; Lipids; Liposomes; Mice; Mice, Inbred ICR

The aim of this study was to evaluate the efficacy and tissue concentration of AmBisome and Fungizone in murine pulmonary aspergillosis, and to investigate the localization of AmBisome at the infection site.. Mice were infected intratracheally with Aspergillus fumigatus. A single dose of each of the antifungals was administered intravenously 4 h after infection. The efficacy of the antifungal treatment was assessed by the pulmonary fungal burden at 20 h post-treatment and the survival time over 1 month. The pulmonary amphotericin B (AMB) concentration was measured until 48 h after administration. The distribution of AmBisome in the lung was evaluated using rhodamine-labelled AmBisome and an anti-AMB antibody.. AmBisome at a dose of > or =1 mg/kg significantly prolonged the survival time of infected mice compared with the control group. At the maximum tolerated dose, 10 mg/kg AmBisome exhibited greater efficacy than 1 mg/kg Fungizone in terms of increasing survival and reducing the fungal burden. The pulmonary AMB concentration of 10 mg/kg AmBisome was higher than that of 1 mg/kg Fungizone. Tissue distribution analysis showed that AmBisome was localized at the infection site in the lung, and this might explain the potent in vivo efficacy in this infection model.. AmBisome is localized at the infection site in the lung and consequently may fully exhibit its in vivo activity. The efficacy of AmBisome is superior to that of Fungizone against pulmonary aspergillosis.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Disease Models, Animal; Humans; Liposomes; Lung; Lung Diseases, Fungal; Male; Mice; Tissue Distribution; Treatment Outcome

Evaluation of the potential of caspofungin, in relation to pharmacokinetics, in order to optimize its use in the treatment of filamentous fungal infections.. The in vitro antifungal activity, pharmacokinetics and therapeutic efficacy of caspofungin versus amphotericin B was investigated in vitro as well as in a model of aerogenic Aspergillus fumigatus infection in neutropenic rats, using rat survival and decrease in fungal burden as parameters for therapeutic efficacy.. In contrast to amphotericin B, caspofungin shows a concentration-dependent gradual decrease in fungal growth in vitro, which makes it difficult to perform visual readings of antifungal activity (CLSI guidelines). The quantitative XTT [2,3-bis(2-methoxy-4-nitro-5-[(sulphenylamino) carbonyl]-2H-tetrazolium-hydroxide] assay measuring a decrease in fungal metabolic activity seems more appropriate for caspofungin susceptibility testing. Using this assay, in vitro caspofungin was 4-fold less active than amphotericin B. In the infection model, therapy was started 16 h after fungal inoculation, and continued once daily for 10 days. Caspofungin was administered intraperitoneally at 1, 2, 3 or 4 mg/kg/day (CAS 1, 2, 3 or 4), amphotericin B at 1 mg/kg/day (AMB 1). Treatment with CAS 1 or AMB 1 provided modest prolongation of animal survival. The combination of caspofungin and amphotericin B did not show additive effects. Increasing the dosage of caspofungin to 2, 3 or 4 mg/kg/day resulted in a dose-dependent significant increase in efficacy. There was 100% survival among rats in the CAS 4 group, which was correlated with a significant decrease in fungal burden, based on the concentration of A. fumigatus galactomannan in serum and lung tissue and quantification of A. fumigatus DNA in lung tissue. Pharmacokinetic analysis suggested that the CAS 4 dose in rats produced drug exposure comparable to the human situation, visualized by similar 24 h AUC and trough concentrations.. The therapeutic efficacy of caspofungin is superior to amphotericin B, which seemed to be discrepant with their in vitro antifungal activity.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Caspofungin; Disease Models, Animal; Echinocandins; Humans; Lipopeptides; Lung; Lung Diseases, Fungal; Microbial Sensitivity Tests; Neutropenia; Peptides, Cyclic; Rats; Treatment Outcome

We evaluated combinations of voriconazole (VRC) and liposomal amphotericin B (L-AMB) in a guinea pig invasive aspergillosis model. Simultaneous VRC and L-AMB was most effective, although VRC monotherapy was also effective. These regimens as well as sequential L-AMB followed by VRC were more effective than L-AMB alone or VRC followed by L-AMB.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Disease Models, Animal; Drug Therapy, Combination; Guinea Pigs; Liposomes; Male; Pyrimidines; Triazoles; Voriconazole

Rats immunosuppressed by the administration of cyclophosphamide and cortisone acetate and then infected with Aspergillus fumigatus were treated with an antifungal drug, EDTA, or a combination of one of the antifungal agents, amphotericin B lipid complex (ABLC; 5 mg/kg of body weight/day for 7 days), and EDTA (30 mg/kg/day for 7 days). The mortality rate was reduced, the duration of survival was increased, fewer A. fumigatus organisms were recovered from the lungs, and less-severe lung lesions were seen histopathologically in the rats receiving the combination treatment than in the rats receiving either an antifungal agent or EDTA alone. Further studies regarding the mechanisms of EDTA and its interactions with ABLC are warranted, and further studies are needed to more fully examine the safety, tolerance, and optimal dosing of EDTA in the treatment of this and other fungal infections.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Calcium; Colony Count, Microbial; Confidence Intervals; Creatinine; Disease Models, Animal; Drug Combinations; Drug Evaluation, Preclinical; Drug Therapy, Combination; Edetic Acid; Lung Diseases, Fungal; Male; Phosphatidylcholines; Phosphatidylglycerols; Rats; Rats, Sprague-Dawley; Survival Analysis; Time Factors

Invasive aspergillosis, an important cause of morbidity and mortality in immunosuppressed (IS) patients, is often treated with amphotericin B lipid formulations. In the present study, liposomal amphotericin B (L-AMB) and amphotericin B lipid complex (ABLC) were compared in treatment of murine pulmonary aspergillosis. Uninfected, IS mice were treated for 4 days with 1, 4, 8, or 12 mg L-AMB or ABLC/kg of body weight, and their lungs were analyzed by high-performance liquid chromatography for drug concentrations. IS mice intranasally challenged with Aspergillus fumigatus were treated with 12, 15, or 20 mg/kg L-AMB or ABLC and monitored for survival, fungal burden (CFU), and tissue drug concentration. Blood urea nitrogen (BUN) levels and kidney histopathology were determined for uninfected and infected mice given 15 or 20 mg/kg L-AMB or ABLC. The results showed that both drugs had therapeutic levels of drug (>3.0 microg/g) in the lungs of uninfected or infected mice, and 24 h after the last dose, ABLC levels were significantly higher than L-AMB levels (P < 0.02). L-AMB and ABLC at 12 mg/kg both produced 57% survival, but only L-AMB at 15 or 20 mg/kg further increased survival to 80 to 90%, with BUN levels and kidney morphology similar to those of controls. Survival at 15 or 20 mg/kg ABLC was not significantly different than that of controls, and BUN levels were significantly elevated, with tubular alterations in uninfected animals and acute necrosis in kidney tubules of infected animals. In conclusion, although both drugs were effective in prolonging survival at 12 mg/kg, the reduced nephrotoxicity of L-AMB increased its therapeutic index, allowing for its safe and effective use at 15 or 20 mg/kg.

Topics: Administration, Inhalation; Aerosols; Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Blood Urea Nitrogen; Colony Count, Microbial; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Combinations; Drug-Related Side Effects and Adverse Reactions; Female; Kidney Tubules; Liposomes; Lung Diseases, Fungal; Mice; Mice, Inbred DBA; Phosphatidylcholines; Phosphatidylglycerols; Survival Analysis; Time Factors

We have evaluated the efficacy of voriconazole (VRC) in a systemic infection by Trichosporon asahii in immunosuppressed guinea pigs. VRC was more effective than amphotericin B in prolonging survival and reducing tissue burden. The best results were obtained with VRC at 10 mg/kg of body weight/day.

Topics: Amphotericin B; Animals; Antifungal Agents; Colony Count, Microbial; Disease Models, Animal; Guinea Pigs; Humans; Kidney; Liver; Microbial Sensitivity Tests; Mycoses; Pyrimidines; Spleen; Survival Analysis; Triazoles; Trichosporon; Voriconazole

CNS aspergillosis is the most frequent and devastating manifestation of dissemination and mortality is high.. Cyclophosphamide-suppressed CD-1 mice were infected intracerebrally with conidia of Aspergillus fumigatus and treated for 10 days with suboptimal doses of Abelcet (4 mg/kg) plus micafungin (1 mg/kg), caspofungin (1 mg/kg), itraconazole (100 mg/kg) or voriconazole (40 mg/kg) and compared with monotherapy. Other groups included conventional amphotericin B (1 mg/kg), Abelcet at 10 or 12 mg/kg or 5% dextrose water (diluent control).. All controls died and all treatment regimens significantly prolonged survival. No monotherapy regimen was superior to another. All dosages of Abelcet and conventional amphotericin B tested were equivalent. Significant enhancement of survival over the respective monotherapies was found only with the combination of Abelcet and voriconazole. Other combinations were not better than Abelcet alone. Recovery of cfu from the brains and kidneys of survivors showed that no regimen was curative. Abelcet and voriconazole showed significantly enhanced efficacy in reducing brain infection. Other combinations showed lower cfu, but no significant enhancement over either drug alone. Dose-escalation of Abelcet alone did not increase reduction of cfu. Recovery from the kidneys showed non-significant reduction of cfu by combinations compared with monotherapies.. Each of the drugs tested had significant efficacy against CNS aspergillosis and Abelcet in combination with voriconazole had enhanced efficacy. Additional studies are warranted.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Brain; Central Nervous System Infections; Colony Count, Microbial; Disease Models, Animal; Drug Combinations; Drug Therapy, Combination; Kidney; Mice; Phosphatidylcholines; Phosphatidylglycerols; Pyrimidines; Survival Analysis; Triazoles; Voriconazole

Mortality from invasive pulmonary aspergillosis approaches 80% with few useful therapeutic options available. In these studies, we examined the efficacy of micafungin (MICA) alone or in combination with other antifungals in a model of pulmonary aspergillosis in immunosuppressed DBA/2 mice infected intranasally with conidia of Aspergillus fumigatus 10AF. In the initial study, groups of mice were given saline, or 1, 3 or 10 mg kg(-1) of MICA b.i.d., s.c. All saline controls, and 90% of untreated mice succumbed to infection. The efficacy of MICA was difficult to assess because of an apparent toxicity at 10 mg kg(-1). MICA given at 1 mg/kg significantly prolonged survival over the saline controls (P = 0.008). MICA at 3 or 10 mg kg(-1) versus the saline controls approached significance. No treatment regimen differed in efficacy. The efficacy of combination therapy was assessed, with mice given either no treatment, MICA at 1 mg/kg/dose, 0.8 mg kg(-1) of intravenous amphotericin B (AMB), 100 mg kg(-1) of oral itraconazole (ICZ), or 100 mg/kg/dose of twice-daily subcutaneous nikkomycin Z (NIK). AMB alone and MICA + AMB or MICA +NIK significantly prolonged survival (P < 0.05 - 0.02) over that of the controls. ICZ alone, ICZ+MICA and NIK alone did not significantly prolong survival. MICA alone at 1 mg/kg approached significance in prolonging survival. The combination of MICA and ICZ appeared to be potentially antagonistic. Although AMB+MICA was efficacious, no synergistic activity was noted for any of the regimens. Overall, these results indicate that MICA has moderate activity against pulmonary aspergillosis and might be useful in combination with conventional AMB.

Topics: Aminoglycosides; Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Disease Models, Animal; Drug Antagonism; Drug Therapy, Combination; Echinocandins; Female; Immunosuppression Therapy; Itraconazole; Lipopeptides; Lipoproteins; Lung Diseases, Fungal; Micafungin; Mice; Mice, Inbred DBA; Peptides, Cyclic; Survival Analysis

A liposomal formulation of Amphotericin B (AmBisome), with small unilamellar vesicles containing amphotericin B, shows characteristic pharmacokinetics as liposomes, and in consequence, has different pharmacological activity and toxicity from amphotericin B deoxycholate (Fungizone). In this study, we evaluated the antifungal pharmacodynamic characteristics of AmBisome against Candida albicans using the in vitro time-kill method and murine systemic infection model. A time-kill study indicated that the in vitro fungicidal activities of AmBisome and Fungizone against C. albicans ATCC 90029 increased with increasing drug concentration. For in vivo experiments, leucopenic mice were infected intravenously with the isolate 4 hr prior to the start of therapy. The infected mice were treated for 24 hr with twelve dosing regimens of AmBisome administered at 8-, 12-, 24-hr dosing intervals. Correlation analysis between the fungal burden in the kidney after 24 hr of therapy and each pharmacokinetic/pharmacodynamic parameter showed that the peak level/MIC ratio was the best predictive parameter of the in vivo outcome of AmBisome. These results suggest that AmBisome, as well as Fungizone, has concentration-dependent antifungal activity. Furthermore, since AmBisome can safely achieve higher concentrations in serum than Fungizone, AmBisome is thought to have superior potency to Fungizone against fungal infections.

Topics: Amphotericin B; Animals; Antifungal Agents; Candida albicans; Candidiasis; Disease Models, Animal; Dose-Response Relationship, Drug; Kidney; Leukopenia; Male; Mice; Microbial Sensitivity Tests

AmBisome is a small unilamellar vesicle containing amphotericin B. AmBisome is generally unable to pass through the blood-brain barrier, but the distribution of AmBisome in the brain is increased by inflammation, and in consequence, AmBisome exhibits activity against fungal meningitis. We investigated the influence of the progression of cryptococcal meningitis on the brain penetration and efficacy of AmBisome.. Mice were infected intracerebroventricularly with Cryptococcus neoformans 4 h or 5 days prior to a single dose treatment.. The brain tissue level and efficacy of AmBisome when administered 5 days after infection were greater than 4 h after infection. An immunohistochemical study showed that AmBisome-derived amphotericin B was localized at the infected site in the subarachnoid space. When AmBisome was compared with Fungizone at the maximum tolerated dose, 10 mg/kg AmBisome exhibited greater efficacy than 1 mg/kg Fungizone in both regimens.. The brain penetration of AmBisome was enhanced by the progression of cryptococcal meningitis and correlated with the in vivo activity.

Topics: Amphotericin B; Animals; Antifungal Agents; Biomarkers; Brain; Cryptococcus neoformans; Disease Models, Animal; Disease Progression; Immunohistochemistry; Male; Maximum Tolerated Dose; Meningitis, Cryptococcal; Mice; Survival Analysis; Time Factors; Treatment Outcome

Evaluating new therapeutic agents for invasive aspergillosis requires animal models that are reproducible among different laboratories. We therefore evaluated a murine model of aerosol infection in two independent laboratories and found a high level of both intra- and interlaboratory reproducibility of survival, fungal burden over time, and the efficacy of liposomal amphotericin B.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Disease Models, Animal; Humans; Liposomes; Lung; Lung Diseases, Fungal; Mice; Reproducibility of Results; Treatment Outcome

To develop proper treatments for patients who do not respond to current antifungal treatments, we tested new combinations of antifungal drugs for treating disseminated infections by Candida glabrata in a murine model.. Mice were rendered neutropenic by intraperitoneal cyclophosphamide and intravenous 5-fluorouracil administration. The animals were infected intravenously with 2 x 10(8) cfu of C. glabrata. The efficacies of micafungin combined with amphotericin B, fluconazole or flucytosine, and of amphotericin B combined with fluconazole were evaluated by survival and tissue burden reduction.. Micafungin plus amphotericin B was the most effective combination at reducing tissue burden. Micafungin at 10 mg/kg combined with amphotericin B at 0.75, 1.5 or 3 mg/kg prolonged survival with respect to the monotherapies, but only the second combination showed a synergistic effect in reducing fungal load in spleen and kidney. Amphotericin B at 1.5 mg/kg combined with micafungin at 5, 10 or 20 mg/kg reduced tissue burden with respect to the monotherapies, but the effects of the three combinations were very similar. These results suggest that amphotericin B in combination with micafungin is promising for the treatment of disseminated C. glabrata infections.

Topics: Amphotericin B; Animals; Antifungal Agents; Candida glabrata; Candidiasis; Colony Count, Microbial; Disease Models, Animal; Drug Synergism; Drug Therapy, Combination; Echinocandins; Fluconazole; Flucytosine; Immunocompromised Host; Kidney; Lipopeptides; Lipoproteins; Micafungin; Mice; Peptides, Cyclic; Spleen; Survival Analysis

The fungal burdens (number of CFU per pair of lungs) in mice infected with Aspergillus fumigatus AB16.4 (for which the amphotericin B [AMB] MIC was elevated) and W73355 (drug-susceptible parent) were reduced by 21 and 81%, respectively, after 5 days of AMB treatment (2 mg/kg/day), indicating that AB16.4 also shows reduced susceptibility to AMB in a murine pulmonary aspergillosis model.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Colony Count, Microbial; Disease Models, Animal; Drug Resistance, Bacterial; Female; Humans; Laboratories; Lung; Lung Diseases, Fungal; Mice; Mice, Inbred DBA

Amphotericin B may cause acute reduction in renal function. N-acetylcysteine (NAC) has a renoprotective activity in several nephrotoxic renal insults, but its effect on amphotericin-induced renal failure has not been investigated yet.. Acute renal failure was induced in 30 Sprague-Dawley rats by a single intraperitoneal injection of amphotericin B (50 mg/kg). NAC (10 mg/kg) in isotonic saline or isotonic saline alone were administered daily for 4 days, starting 1 day before the amphotericin B injection. Glomerular filtration rate (GFR) was assessed using 99m-technetium diethylene triaminepentaacetic acid. Before and following amphotericin B administration, a 24-hour urine collection was performed for sodium, potassium and magnesium determination. The kidneys were preserved for pathologic examination.. Amphotericin B induced a significant decrease of GFR in both groups. Four days after amphotericin injection the GFR in the NAC-treated group was significantly higher than in the control group (0.62 +/- 0.20 vs. 0.46 +/- 0.14 ml/min, p = 0.042). Histologic signs of acute tubular necrosis were attenuated in the NAC-treated group. There were no significant differences between the groups in sodium, potassium and magnesium urine excretion after amphotericin injection.. NAC treatment exerted a renoprotective effect on deterioration of GFR in a rat model of amphotericin-induced renal failure. No functional protection on tubular function, as obviated by similar polyuria and urine losses of potassium and magnesium in both groups, was observed.

Topics: Amphotericin B; Animals; Disease Models, Animal; Glomerular Filtration Rate; Kidney Diseases; Male; Rats; Rats, Sprague-Dawley; Treatment Outcome

Candida albicans is the most frequent cause of fungal keratitis in temperate regions. Caspofungin has potent activity against Candida spp. in a variety of clinical settings. Little is known, however, about its activity against fungal keratitis. We compared the efficacy of topical caspofungin with that of topical amphotericin B (AMB) in a rabbit model of experimental keratomycosis. Keratitis was induced with a standardized inoculum of Candida albicans (SC 5314) placed on the debrided cornea. Twenty-four hours after infection, animals were randomly assigned to treatment with 0.15% caspofungin, 0.5% caspofungin, 0.15% AMB, and a saline control (n = 12 rabbits in each group). For the first 12 h, treatment was repeated every 30 min and, after a 12-h pause, was resumed at hourly intervals for another 12 h. The animals were examined and killed 12 h after administration of the last dose. Treatment effects were evaluated by clinical assessment, fungal culture, and histopathology. Drug treatment significantly reduced corneal fungal recovery from 3.78 log10 CFU in saline-treated animals to 2.97, 1.76, and 1.18 log10 CFU in animals treated with 0.15% caspofungin, 0.5% caspofungin, and 0.15% AMB, respectively. By histopathology, the mean hyphal density was significantly lower in the corneas of treated animals than in those of the controls; there was no difference in hyphal densities between the different treatment groups. The depth of corneal invasion was not significantly reduced by the antifungal treatments. By clinical assessment, keratitis progressed in animals treated with saline, whereas disease progression was inhibited by all drug treatment regimens. In our rabbit model, 0.5% caspofungin was as effective as 0.15% AMB for the topical treatment of Candida keratitis. The potential clinical efficacy of caspofungin awaits further investigation.

Topics: Administration, Topical; Amphotericin B; Animals; Antifungal Agents; Candida albicans; Candidiasis; Caspofungin; Disease Models, Animal; Echinocandins; Eye Infections, Fungal; Humans; Keratitis; Lipopeptides; Male; Peptides, Cyclic; Rabbits; Treatment Outcome

Ever since their discovery about 60 years ago as therapeutic agent for visceral leishmaniasis (VL) or kala-azar, pentavalent antimonials (Sb(v)) have remained the first line treatment of choice all over the world including India. But recently, the number of kala-azar patients unresponsive to sodium stibogluconate (SSG) therapy, is steadily increasing in India. In this study, three clinical isolates, of which two were from SSG unresponsive and one from SSG responsive patients were evaluated for their infectivity and for their chemotherapeutic responses in vitro (macrophage-amastigote system) and in vivo (in hamsters). Persistence of SSG resistance was also checked by repeated passages in vitro as well as in vivo. The drug resistant strains (2039 and 2041) did not respond to SSG therapy both in vitro as well as in vivo but strains 2001 and Dd8 showed full sensitivity to SSG treatment. All the four strains responded well to amphotericin B and miltefosine treatment both in macrophages and in hamsters. The specific chemotherapeutic responses of all the strains to SSG were consistently persistent after repeated passages in cultures and in vivo, which indicates that these isolates are truly refractory to SSG treatment in field conditions. Two isolates were also transfected with green fluorescent protein (GFP) for the development of in vitro assay for studying antileishmanial activities of new and reference drugs in macrophages by flow cytometry.

Topics: Amphotericin B; Animals; Antimony Sodium Gluconate; Antiprotozoal Agents; Cell Line; Cricetinae; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Resistance; Humans; Leishmania donovani; Leishmaniasis, Visceral; Macrophages; Male; Mesocricetus; Mice; Parasitic Diseases, Animal; Phosphorylcholine

In view of the poor therapy outcomes of invasive aspergillosis, the objective of this study was to evaluate the efficacy of combination treatment consisting of the polyene amphotericin-B-intralipid, the echinocandin caspofungin and granulocyte-colony stimulating factor (G-CSF) in experimental murine systemic aspergillosis. With inhibition of synthesis of 1,3-beta-d-glucan in the fungal cell wall by caspofungin and an effect on the cell membrane by amphotericin-B-intralipid, this treatment may result in a synergic effect against Aspergillus fumigatus. Addition of G-CSF may further contribute to therapy of aspergillosis.. ICR mice were immunosuppressed by intraperitoneal administration of cyclophosphamide. Three days later, the mice were inoculated intravenously (iv) with A. fumigatus conidia. Infection and treatment were evaluated during an observation period of 30 days in terms of mortality (survival rate and mean survival time) and morbidity (quantitative determination of fungal burden, histopathology, and detection of serum galactomannan).. Combination of caspofungin + G-CSF or addition of G-CSF to the combination of caspofungin + amphotericin-B-intralipid increased the survival rate of infected mice up to 78.9% and prolonged their mean survival time to 25 days. These combinations also resulted in a reduction in fungal burden in organs, and a decrease in serum galactomannan.. The successful results obtained in the experimental model may possibly open the way to more effective management of aspergillosis in humans.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Caspofungin; Disease Models, Animal; Drug Synergism; Drug Therapy, Combination; Echinocandins; Female; Galactose; Granulocyte Colony-Stimulating Factor; Immunocompromised Host; Kidney; Lipopeptides; Liposomes; Lung; Mannans; Mice; Mice, Inbred ICR; Peptides, Cyclic; Polyenes; Survival Rate

To compare the activity of aminocandin (IP960), a new echinocandin with broad-spectrum in vitro activity against Aspergillus and Candida spp., with that of amphotericin B and fluconazole in a temporarily immunocompromised murine model of disseminated candidiasis.. Mice were rendered neutropenic with cyclophosphamide and infected intravenously 3 days later with a fluconazole-resistant Candida tropicalis strain. Mice were treated with intraperitoneal amphotericin B (5 mg/kg/dose), oral fluconazole (50 mg/kg/dose), intravenous aminocandin (0.1--5 mg/kg/dose) or solvent control for 9 days. Mice were observed for survival and survivors were sacrificed 11 days post-infection. Kidneys, liver, brain and lungs were removed for semi-quantitative culture.. Control mice had 90--100% mortality. After infection with C. tropicalis, aminocandin 2.5 and 5 mg/kg/day and amphotericin B yielded 80% survival; aminocandin 1 mg/kg/day yielded 70% survival; aminocandin 0.25 and 0.1 mg/kg/day yielded 30% and 20% survival, respectively; and fluconazole 50 mg/kg/day and control regimens yielded 10% and 0--10% survival, respectively. Aminocandin 2.5 and 5.0 mg/kg/day and amphotericin B were superior in reducing mortality compared with aminocandin 0.25 and 0.1 mg/kg/day, fluconazole and controls (P<0.047). The only regimen to reduce organ burdens below detectable levels was amphotericin B, which cleared 40% of mice. All organ burdens in the aminocandin 1.0, 2.5 and 5.0 mg/kg/day and amphotericin B regimens were significantly lower than other groups (P<0.02).. The data demonstrate that aminocandin at doses of >or=1.0 mg/kg/day is as effective as amphotericin B at improving survival and reducing organ burdens in this murine model of disseminated C. tropicalis.

Topics: Amphotericin B; Animals; Antifungal Agents; Candida tropicalis; Candidiasis; Cyclophosphamide; Disease Models, Animal; Drug Resistance, Fungal; Fluconazole; Immunocompromised Host; Lipopeptides; Lipoproteins; Male; Mice; Mice, Inbred Strains; Neutropenia; Survival Rate; Treatment Outcome

This study was conducted to evaluate the effectiveness of a new antifungal drug, micafungin, and standard antifungal drugs against endophthalmitis induced in a rabbit by intravitreal injection of Aspergillus fumigatus, an important fungal pathogen. Effectiveness was evaluated by the preservation of b-wave amplitude at 72 h after injection of the fungus relative to the b-wave amplitude at baseline before any intravitreal injections. A 0.06 ml inoculum of 10(6) conidia of A. fumigatus was injected into the vitreous of the right eye of all rabbits; and, 12 h later, a 0.06 ml solution containing one of 3 antifungal drugs or saline was injected into the vitreous of both eyes. All three antifungal drugs produced significant b-wave preservation at 72 h in infected eyes compared to that in infected eyes receiving saline injections. There was no statistically significant difference between the effects of micafungin and amphotericin B in the right eyes with fungal endophthalmitis, and both produced significantly more preservation of b-wave amplitude than voriconazole. Amphotericin B, but neither micafungin nor voriconazole produced significant reduction of the b-wave amplitude in the left eyes.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Disease Models, Animal; Echinocandins; Electroretinography; Endophthalmitis; Eye Infections, Fungal; Follow-Up Studies; Lipopeptides; Lipoproteins; Micafungin; Ophthalmoscopy; Peptides, Cyclic; Pyrimidines; Rabbits; Retina; Triazoles; Vitreous Body; Voriconazole

The nebulization of amphotericin B desoxycholate (AMB-DOC), liposomal amphotericin B (L-AMB), amphotericin B lipid complex (ABLC) and amphotericin B colloidal dispersion (ABCD) has been investigated. Particle sizes of generated aerosol droplets were measured. Pulmonary amphotericin B deposition and amphotericin B concentration in blood directly after nebulization and at six weeks after nebulization was measured in healthy rats. The efficacy of nebulized amphotericin B formulations was evaluated in persistently granulocytopenic rats with invasive pulmonary aspergillosis. Treatment was given either after or before fungal inoculation. The endpoint was survival of animals. Aerosol particle sizes, expressed as the values for the mass median diameter were 1.38, 2.43, 0.90 and 2.29 microm for AMB-DOC, L-AMB, ABLC and ABCD, respectively. Amphotericin B concentrations in the lungs directly after nebulization exceeded the minimum inhibitory concentration of Aspergillus fumigatus and amphotericin B was still detected in lungs of rats at six weeks after nebulization. Treatment, started at 16 h after fungal inoculation, resulted in a significantly prolonged survival as compared with sham-treated rats for all four formulations. Prophylactic treatment at one week before fungal inoculation resulted in a significantly prolonged survival for all four formulations. Aerosol treatment given at two weeks before inoculation was effective only for AMB-DOC and L-AMB, whereas treatment given at six weeks resulted in a significantly prolonged survival for L-AMB only. All commercially available amphotericin B preparations could be nebulized efficiently and may be of value in the prophylactic treatment of invasive pulmonary aspergillosis.

Topics: Administration, Inhalation; Aerosols; Agranulocytosis; Amphotericin B; Animals; Antifungal Agents; Aspergillosis, Allergic Bronchopulmonary; Aspergillus fumigatus; Disease Models, Animal; Female; Humans; Lung; Microbial Sensitivity Tests; Particle Size; Product Surveillance, Postmarketing; Pulmonary Surfactants; Rats; Specific Pathogen-Free Organisms; Survival Analysis; Time Factors

Central nervous system (CNS) aspergillosis is a severe disease that responds poorly to current therapies. The current studies examined the efficacies of several antifungal agents alone or in combination with a murine model of CNS aspergillosis. Immunosuppressed mice were infected intracerebrally with Aspergillus fumigatus and treated with an amphotericin B preparation, an echinocandin, or voriconazole (VCZ) given alone or in combination. Monotherapy studies showed that micafungin (MICA), caspofungin (CAS), VCZ, conventional amphotericin B (AMB), Abelcet (ABLC) (a lipid-carried AMB formulation; Enzon Pharmaceuticals, Inc.), and AmBisome (AmBi) (liposomal AMB; Gilead Sciences, Inc.) were efficacious. However, doses of AmBi above 15 mg/kg of body weight showed reduced efficacy. Neither MICA nor CAS showed dose responsiveness at the doses tested (1, 5, or 10 mg/kg). Only the 40-mg/kg dose of VCZ was effective. AmBi and ABLC showed dose responsiveness, with 10-mg/kg doses causing a significant reduction in fungal burden; they had equivalent activities at the 10-mg/kg dose. Suboptimal dosages of AmBi in combination with MICA, CAS, or VCZ were effective in prolonging survival. However, significantly enhanced activity was demonstrated only with AmBi and VCZ in combination. AmBi in combination with MICA or CAS showed a trend toward enhanced activity, but the combination was not significantly superior to monotherapy. The use of AmBi with CAS or VCZ at optimal doses did not improve efficacy. Cure was not attained with any dosage combinations. These results indicate that AmBi in combination with VCZ may be superior for treatment of CNS aspergillosis; combinations of AmBi and MICA or CAS were not antagonistic and may have a slight benefit.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Caspofungin; Central Nervous System Fungal Infections; Disease Models, Animal; Drug Combinations; Drug Therapy, Combination; Echinocandins; Lipopeptides; Lipoproteins; Liposomes; Micafungin; Mice; Peptides, Cyclic; Pyrimidines; Triazoles; Voriconazole

While Candida albicans remains the most common Candida isolate, Candida glabrata accounts for approximately 15 to 20% of all Candida infections in the United States. In this study we used immunosuppressed mice infected with C. glabrata to investigate the efficacy of liposomal amphotericin B alone or in combination with the echinocandin caspofungin or micafungin. For monotherapy, mice were given six daily doses of liposomal amphotericin B (3 to 20 mg/kg of body weight), caspofungin (1 to 5 mg/kg), or micafungin (2.5 to 10 mg/kg). With concomitant therapy, mice received liposomal amphotericin B (7.5 mg/kg) in addition to caspofungin (2.5 mg/kg) or micafungin (2.5 mg/kg) for 6 days. For sequential therapy, liposomal amphotericin B was administered on days 1 to 3 and caspofungin or micafungin was given on days 4 to 6; conversely, caspofungin or micafungin was administered on days 1 to 3 and liposomal amphotericin B was given on days 4 to 6. Efficacy was based on the number of CFU per gram of kidney 21 days postchallenge. Monotherapy with liposomal amphotericin B (7.5 to 20 mg/kg) was significantly more effective than no drug treatment (control group) (P < 0.05) and demonstrated a dose-dependent response, with 20 mg/kg lowering the CFU/g from 6.3 to 4.2 (significantly different from the value for the control group [P < 0.001]). Monotherapy with all echinocandin doses lowered the CFU/g from 6.0 to 6.4 to 2.7 to 3.3 (significantly different from the value for the control group [P < 0.001]) with no dose-dependent response. Complete clearance of infection could be achieved only when liposomal amphotericin B was given either concomitantly with caspofungin or micafungin or if liposomal amphotericin B was given sequentially with caspofungin. In conclusion, the combination of liposomal amphotericin B with an echinocandin markedly improved the therapeutic outcome in murine C. glabrata systemic infection.

Topics: Amphotericin B; Animals; Antifungal Agents; Candida; Candidiasis; Caspofungin; Disease Models, Animal; Drug Therapy, Combination; Echinocandins; Immunocompromised Host; Lipopeptides; Lipoproteins; Liposomes; Micafungin; Mice; Peptides, Cyclic

The objective of this research was the evaluation of the activity of admixtures of amphotericin B (AMB)--intralipid (AMB-IL) and nystatin (Ny)--intralipid (Ny-IL) against experimental systemic aspergillosis in immunocompromised mice. ICR mice were transiently immunosuppressed by intraperitoneal (i.p.) administration of cyclophosphamide (CY). Three days post CY administration the mice were inoculated intravenously (i.v.) with Aspergillus fumigatus conidia. The animals were treated with various doses of AMB-IL or Ny-IL admixtures administered i.v. for 5 consecutive days, starting 2 h after infection. The mean survival rate (MSR) and mean survival time (MST) were evaluated during an observation period of 30 days in comparison to untreated infected mice and to animals treated with conventional formulations of these drugs. These experiments showed that AMB-IL increased significantly the MSR. Specifically, the MSR ranged in dependence of dose, between 48 and 65.7% vs. 0% of the untreated (P < 0.001, anova analysis) and 39.7% of AMB-treated animals (P < 0.01). The MSR of the Ny-IL-treated mice ranged between 16.2 and 40% in comparison to 0% of the untreated group (P < 0.001). Treatment with both admixtures prolonged the MST of the mice (AMB-IL: 17.3-23.07 days; Ny-IL: 8.61-16.8 days) in comparison to either untreated (6.13 days) or AMB treated animals (15.23 days). The data obtained in this study show that both AMB-IL and Ny-IL formulations, particularly AMB-IL at the highest dose, were effective in the treatment of experimental systemic aspergillosis.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Disease Models, Animal; Drug Combinations; Drug Therapy, Combination; Fat Emulsions, Intravenous; Female; Immunocompromised Host; Immunosuppressive Agents; Mice; Mice, Inbred ICR; Nystatin; Phosphatidylcholines; Phosphatidylglycerols; Polyenes

We developed a novel model of invasive aspergillosis (IA) that recapitulates human disease. Mice were immunosuppressed with cyclophosphamide and cortisone acetate and then infected in an aerosol chamber. This procedure reproducibly delivered 1 x 10(3) to 3 x 10(3) conidia to the lungs. Lethal pulmonary IA developed over 2 weeks and was prevented by amphotericin B.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis, Allergic Bronchopulmonary; Atmosphere Exposure Chambers; Cortisone; Costs and Cost Analysis; Cyclophosphamide; Disease Models, Animal; Disease Progression; Female; Immunosuppressive Agents; Inhalation Exposure; Leukopenia; Lung; Mice; Mice, Inbred BALB C; Pulmonary Alveoli; Reproducibility of Results; Survival Analysis

Amphotericin B may be employed as a potentially toxic deoxycholate complex or incorporated in liposomes and other particles which have an altered tissue distribution. A combination of both preparations could help to overcome the drawbacks of the individual preparations. We have employed a mouse model of systemic infection with Candida albicans to investigate whether this assumption was essentially true. We found that the combination of low dosages of both preparations (0.5 mg/kg of body weight/day of conventional and 0.5 mg kg of body weight/day liposomal amphotericin B) was more efficient than a similar dosage of conventional amphotericin B (1 mg/kg of body weight/day) in the liver and similar or higher dosages of liposomal amphotericin B (1 or 5 mg/kg of body weight/day) in the kidneys.

Topics: Amphotericin B; Animals; Candida albicans; Candidiasis; Chemistry, Pharmaceutical; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Administration Schedule; Drug Carriers; Female; Fungemia; Liposomes; Mice; Mice, Inbred BALB C; Probability; Sensitivity and Specificity; Treatment Outcome

The efficacy of voriconazole in combination with amphotericin B or micafungin was studied in a transiently neutropenic guinea-pig model of invasive pulmonary aspergillosis. Guinea-pigs treated with the antifungal drugs, alone or in two-drug combinations, had an improved survival rate and reduced fungal burden in the lungs compared to untreated control animals. The efficacy of monotherapy and combination therapy was similar; activity was neither enhanced nor reduced with the two-drug combinations. Further studies of efficacy, dosing and optimal regimens for antifungal combinations are warranted.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Colony Count, Microbial; Disease Models, Animal; Drug Therapy, Combination; Echinocandins; Female; Guinea Pigs; Lipopeptides; Lipoproteins; Lung; Lung Diseases, Fungal; Micafungin; Peptides, Cyclic; Pyrimidines; Survival Analysis; Triazoles; Voriconazole

Cerebral scedosporiosis is a life-threatening infection that is difficult to treat. The aim of this work was to develop a murine model of cerebral infection by Scedosporium apiospermum using intracranial inoculation and to use this model to evaluate the efficacy of amphotericin B deoxycholate and liposomal amphotericin B.. Mice were rendered neutropenic by intraperitoneal cyclophosphamide and intravenous (iv) 5-fluorouracil administration. Animals were infected with iv or intracranial inoculation of 1 x 10(4), 5 x 10(4) or 5 x 10(5) cfu of a clinical strain of S. apiospermum. Tissue burden reduction was determined in kidneys and brain 4 days after the infection. Efficacy of amphotericin B and liposomal amphotericin B (0.8 mg/kg/day intraperitoneally and 40 mg/kg/day iv, respectively) was evaluated in neutropenic mice infected iv or intracranially with 5 x 10(4) cfu. Survival was analysed with the log-rank test. Fungal burden values of different groups were compared using the Mann-Whitney U-test.. In our model, intracranial infection produced a higher fungal load in the brain and a lower fungal load in the kidney than iv inoculation. Survival of animals infected intracranially and treated with amphotericin B or liposomal amphotericin B (mean survival time = 8.3 and 9.2 days, respectively) was not different from the control group (P=0.58 and 0.85, respectively).. We have developed a murine model of cerebral scedosporiosis, which may be useful for studying various pathological aspects of this infection and evaluating new therapeutic approaches. Amphotericin B and liposomal amphotericin B were unable to resolve the infection.

Topics: Amphotericin B; Animals; Antifungal Agents; Brain; Brain Diseases; Disease Models, Animal; Humans; Liposomes; Male; Mice; Mycetoma; Neutropenia; Scedosporium; Treatment Failure

This study was done to determine whether high dose AmBisome (4-20 mg/kg), given intermittently, could reduce the frequency of dosing needed to treat murine systemic candidiasis when compared with conventional daily treatment.. Mice were immunosuppressed with cyclophosphamide every 3 days, beginning day -3 before challenge with log(10) 5.0 cfu Candida albicans. Treatment was begun 48-72 h post-challenge with daily or intermittent dose regimens of AmBisome, followed by determination of kidney cfu for up to 1 month post-treatment.. A single AmBisome dose of 4 mg/kg was as effective as four daily, 1 mg/kg treatments. A total of 8 mg/kg, given as 4 mg/kg on days 2 and 4, or as 5 mg/kg on day 2 followed by 1 mg/kg on days 3, 4, and 5, also produced comparable efficacy. While 20 mg/kg given day 2, 4 and 6 post-challenge as a 1 week loading dose, followed by one 10 mg/kg treatment on day 13, decreased the fungal burden by up to 5 logs compared with controls (log(10) 2.3 cfu/g and log(10) 7.5 cfu/g, respectively), 20 mg/kg given Monday, Wednesday and Friday for 5 weeks, reduced the fungal burden to undetectable levels (i.e. log(10) 1.0 cfu).. Significant reduction or clearance of kidney cfu, following intermittent, high dose AmBisome treatment, indicated that non-daily dosing regimens could be successfully used instead of conventional daily dosing to treat established C. albicans infection in immunosuppressed mice.

Topics: Amphotericin B; Animals; Antifungal Agents; Candida albicans; Candidiasis; Colony Count, Microbial; Disease Models, Animal; Drug Administration Schedule; Female; Immunocompromised Host; Kidney; Liposomes; Mice; Mice, Inbred C57BL; Treatment Outcome

A broth microdilution method was used for testing amphotericin B against 33 clinical isolates of Candida tropicalis. All isolates were in vitro susceptible to the polyene (MIC [minimal inhibitory concentration] < or = 1.0 microg/mL). However, when the isolates were cultured in a medium containing amphotericin B at a concentration of 1.5 microg/mL, a wide interstrain variation of growth rate was observed. Five isolates (15%) proved to be highly tolerant to the drug and grew at a frequency ranging from 1 x 10(-1) to 2 x 10(-2). Twenty-three isolates (70%) grew at a frequency ranging from 1 x 10(-5) to 1 x 10(-8). The remaining five isolates (15%) failed to grow in drug-containing medium. In general, this growth variation was not associated with amphotericin B MICs displayed by the single isolates. In addition, the strains grown in drug-containing medium did not represent amphotericin B-resistant mutants, as shown by the maintenance of MICs similar to those of their respective parent isolates. Killing experiments conducted in selected isolates confirmed a variation of fungicidal activity of amphotericin B. To see whether this phenomenon was associated with a variation of amphotericin B response in vivo, we established an experimental model of systemic murine candidiasis in CD1 mice by intravenous injection of cells belonging to Candida tropicalis 3147 (growth rate at a frequency of 1 x 10(-1) in amphotericin B medium) and Candida tropicalis 4055 (no growth). Low (0.3 mg/kg/day) and high (1 mg/kg/day) doses of amphotericin B were both effective at reducing the fungal burdens in the kidneys of mice infected with either strain (p, 0.01 to 0.02). However, whereas the burden of mice infected with isolate 3147 and treated with the polyene at 0.3 mg/kg/day was reduced by 1.2 +/- 0.25 (mean +/- standard deviation) log10 cfu/g compared to untreated mice, the same dosing regimen yielded a burden reduction of 2.6 +/- 0.07 log10 cfu/g in mice infected with isolate 4055 (p < 0.001). Similarly, amphotericin B at 1 mg/kg/day yielded a burden reduction of 1.8 +/- 0.20 vs. 2.5 +/- 0.30 log10 cfu/g in mice infected with isolates 3147 and 4055, respectively (p < 0.001). Our data revealed a variable pattern of tolerance to amphotericin B among isolates of Candida tropicalis and showed that this phenomenon might influence the rate of organ clearance during therapy.

Topics: Amphotericin B; Animals; Antifungal Agents; Candida tropicalis; Candidiasis; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Resistance, Fungal; Immunosuppression Therapy; Male; Mice; Mice, Inbred Strains; Microbial Sensitivity Tests

Amphotherin B was formulated in a nanosuspension as a new oral drug delivery system for the treatment of experimental visceral leishmaniasis. Amphotericin B (AmB) nanosuspensions were produced by high pressure homogenisation obtaining particles with a PCS diameter of 528 nm. Environmental stability was determined in artificial gastrointestinal fluids at different pH and electrolyte concentrations. In vivo efficacy was determined in a mouse model of visceral leishmaniasis. Following oral administration (5 mg kg(-1)), micronised amphotericin B did not show any curative effect. However, administrations of amphotericin B nanosuspension, reduced liver parasite load by 28.6% compared to untreated controls.

Topics: Administration, Oral; Amphotericin B; Animals; Chemistry, Pharmaceutical; Disease Models, Animal; Drug Carriers; Drug Delivery Systems; Drug Stability; Hydrogen-Ion Concentration; In Vitro Techniques; Leishmaniasis; Liver; Mice; Mice, Inbred BALB C; Microscopy, Electron; Microspheres; Nanotechnology; Parasitic Sensitivity Tests; Spectrum Analysis; Time Factors; Water-Electrolyte Balance

A conventional and easy method to establish a murine oral candidiasis model, which has not only a stable yeast population in the oral cavity but also symptoms characteristic of oral thrush, was developed by using a sedative agent. Mice were immunosuppressed with prednisolone and were given tetracycline hydrochloride. They were orally infected with 10(6) viable cells of Candida albicans by means of a cotton swab and enough chlorpromazine chloride had been injected to keep them in a sedative state about for 3 hr after inoculation. From day 3 to day 7 post inoculation, 10(5)-10(6) colony forming units of Candida were recovered from the oral cavity of each mouse and whitish, curd-like patches were observed on most parts of tongue. Microscopically, germ tubes had appeared on the tongue surface. This model would be a useful experimental oral candidiasis for investigating the pathogenesis of C. albicans oral infection and the efficacy of various antifungal agents microbiologically and symptomatically.

Topics: Amphotericin B; Animals; Antifungal Agents; Candida albicans; Candidiasis, Oral; Chlorpromazine; Disease Models, Animal; Female; Fluconazole; Immunocompromised Host; Mice; Mice, Inbred ICR; Prednisolone; Tetracycline; Virulence

Inhalation of water contaminated with Naegleria fowleri may lead to a potentially fatal infection of the central nervous system known as primary amebic meningoencephalitis (PAM). Amphotericin B (AMB), an antifungal drug, is the only agent with established clinical efficacy in the treatment of PAM, though therapy with this drug is not always effective and has been associated with adverse effects on the kidneys and other organs. We investigated the activity of various therapeutic agents against N. fowleri in an attempt to identify other useful agents for treating PAM. Several of these agents exhibited in vitro activity against the Lee (M67) strain of N. fowleri. The minimum inhibitory concentrations of these agents were 0.1 microg/ml (ketoconazole), 1 microg/ml (liposomal AMB), and 10 microg/ml (minocycline, quinupristin-dalfopristin, and trifluoperazine). Other agents had a minimum inhibitory concentration > 10 microg/ml (linezolid) or > 100 microg/ml (rifampin). In a mouse model of PAM, none of the untreated control mice survived, whereas the survival of treated animals was 50% (quinupristin-dalfopristin), 30% (ketoconazole and liposomal AMB), 20% (trifluoperazine), and 10% (linezolid and minocycline). Further studies are needed to ascertain whether these agents have synergistic activity with AMB in vitro and in vivo.

Topics: Acetamides; Adolescent; Amebiasis; Amebicides; Amphotericin B; Animals; Central Nervous System Protozoal Infections; Disease Models, Animal; Drug Therapy, Combination; Female; Humans; Ketoconazole; Linezolid; Liposomes; Male; Mice; Minocycline; Naegleria fowleri; Oxazolidinones; Trifluoperazine; Virginiamycin

This study evaluated the value of polymerase chain reaction (PCR) for diagnosing and monitoring of invasive aspergillosis during amphotericin B therapy. PCR, microscopy and culture of tissues samples (n = 126) and blood samples (n = 78) of experimentally infected mice (n = 42) were performed. The PCR results of treated were compared to those of untreated animals; Aspergillus fumigatus and A. terreus were used in this study. In the amphotericin B treated group the sensitivities of PCR, microscopic examination and culture of the various tissues were 69, 58, and 53%, respectively; the specificities of all examinations were 100%. In the untreated group the sensitivities of PCR, microscopic examination, and culture were 72, 64, and 57%, respectively; the specificities of all examinations were 100%. The 78 blood samples taken from mice under therapy were tested by PCR over a period of 8 days following Aspergillus infection. The test sensitivity was 77%, the specificity 46%, the positive predictive value 59%, and the negative predictive value 67%. In the untreated group the sensitivity was 92%, the specificity 46%, the positive predictive value 63%, and the negative predictive value 86%. The results suggest that this PCR method has possible clinical value for improving the diagnosis of invasive Aspergillus infection. Monitoring of blood under antifungal therapy is not recommended.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Disease Models, Animal; DNA, Fungal; Female; Fungemia; Mice; Mice, Inbred BALB C; Polymerase Chain Reaction; Reference Values; Sensitivity and Specificity

Invasive pulmonary aspergillosis is frequent in neutropenic patients. Usually localized in the beginning, the disease spreads and mortality is high despite antifungal treatment. The role of early adjuvant surgery is not clear. Surgery may help to confirm fungal disease, may control fungal disease locally and may prevent systemic spreading. This study examines effects of early resection on survival and dissemination in a rat model of localized invasive pulmonary aspergillosis.. Forty persistently neutropenic male albino rats were challenged with standardized conidial aspergillus inoculum injected into peripheral lung tissue of the right upper lobe under direct vision. Animals were divided into four groups. Twenty animals were treated with amphotericin B at 1 mg/kg per day beginning 48 h after inoculation, 20 animals were left untreated. In each group half the animals underwent early resection of localized invasive aspergillosis by lobectomy. Animals were checked daily and mortality was recorded up to 28 days after which surviving animals were sacrificed.. Significantly higher survival was observed in resected animals in the non-Am B groups (survival: 10 +/- 19% without early resection and 50 +/- 32% with early resection; P = 0.044). However, early resection did not lead to improved survival in animals treated with amphotericin B (survival 70 +/- 29% without early resection and 50 +/- 32% with early resection; P = 0.316).. In this rat model of localized invasive pulmonary aspergillosis effects of early resection on survival could be demonstrated only in animals not receiving amphotericin B treatment.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Combined Modality Therapy; Disease Models, Animal; Lung Diseases, Fungal; Male; Neutropenia; Opportunistic Infections; Rats; Rats, Sprague-Dawley; Survival Rate

In this study we developed a highly reproducible intracranial murine model of cryptococcosis. Mice (Balb/c, 5-7 weeks old) were challenged intracranially and treated with intermediate (30 mg/kg) or high (90 mg/kg) dose fluconazole, and amphotericin B (0.75 mg/kg), administered singly or in combination with flucytosine (100 mg/kg). Survival and brain CFU analyses were performed. Effect of fluconazole prophylaxis was also determined. Our data show that the developed model mimics clinical signs of cryptococcal meningitis. In single treatment, fluconazole (30 mg/kg) was more efficacious than amphotericin B or flucytosine (P < 0.0001). Combination treatment led to significantly increased anticryptococcal activity, which was highest for high dose fluconazole + flucytosine (P < 0.0001). However, no significant difference was observed between high dose fluconazole treatment with and without flucytosine (P >0.05). Fluconazole prophylaxis led to a significant decrease in brain CFU. In conclusion, high dose fluconazole administered post-infection, or as prophylaxis, may be highly efficacious in the treatment and prevention of meningoencephalitis.

Topics: Amphotericin B; Animals; Antifungal Agents; Brain; Cryptococcus neoformans; Disease Models, Animal; Drug Therapy, Combination; Fluconazole; Flucytosine; Meningitis, Cryptococcal; Mice; Mice, Inbred BALB C; Microbial Sensitivity Tests; Survival Rate

Micafungin is a new echinocandin with broad-spectrum in vitro and in vivo antifungal activity against both Aspergillus and Candida species. We compared the activity of micafungin with that of amphotericin B and fluconazole in a persistently immunocompromised murine model of disseminated candidiasis against a strain of Candida tropicalis that was resistant to amphotericin B and fluconazole in vitro. Mice were rendered persistently neutropenic with multiple doses of cyclophosphamide and infected intravenously with C. tropicalis. Mice were treated with either intraperitoneal amphotericin B (0.5-5 mg/kg per dose), oral fluconazole (50 mg/kg twice a day), intravenous micafungin (1-10 mg/kg per dose) or solvent control for 7 days. Mice were killed at 11 days post-infection and kidneys, lungs, brain and liver removed for quantitative culture. Overall mortality in the model was low, with rates varying between 10% and 25% in treatment groups. Micafungin at doses between 2 and 10 mg/kg were the only regimes able to reduce cfu below the level of detection of tissues infected with C. tropicalis. Micafungin was well tolerated by the mice and was much more effective than amphotericin B or fluconazole against an amphotericin B- and fluconazole-resistant C. tropicalis.

Topics: Amphotericin B; Animals; Antifungal Agents; Candida tropicalis; Candidiasis; Disease Models, Animal; Echinocandins; Lipopeptides; Lipoproteins; Male; Micafungin; Mice; Neutropenia; Peptides, Cyclic

Radioprotective and antineoplastic activity of polyene, its derivatives and combinations with dimethyl sulfoxide (DMSO) was studied. The most potent radioprotective effect was demonstrated by methylated levorin, original levorin and by its isomer--isolevorin. Survival rate of the animals on 12th day after X-ray exposure was 100, 60, 60 per cent, at the control group 33.6, 20 and 0 per cent consequently. Levorin and alkyl derivatives of amphotericin B--methamphocin and buthamphocin inhibited growth of ascites and solid tumors to 46.3-79.0 per cent when compared to control group. Polyen antibiotics combined with DMSO also demonstrated antineoplastic activity at the animals treated with carcinogenic agent--diethyl nitrosoamine (DENA). 5-month survival of the animals was 76 per cent at nystatin and levorin group and 35.7 per cent at the control group (animals treated with DENA only).

Topics: Amphotericin B; Animals; Anti-Bacterial Agents; Candicidin; Diethylnitrosamine; Dimethyl Sulfoxide; Disease Models, Animal; Drug Therapy, Combination; Female; Male; Mice; Neoplasms, Experimental; Polyenes; Radiation Injuries, Experimental; Rats; Solvents; Survival Rate; Time Factors

We established a reproducible lethal disseminated infection by the opportunistic fungus Scedosporium prolificans in an immunosuppressed murine model. We compared the effectiveness of the combined administration of liposomal amphotericin B (LAMB) and granulocyte colony-stimulating factor (G-CSF) with that of either agent alone and with that of amphotericin B deoxycholate (AMB). LAMB + G-CSF and LAMB treatments improved survival significantly with respect to the untreated control. The mean survival times of these three groups were 13.2, 9.1 and 7.9 days, respectively. Culture results in terms of colony counts for samples of deep organs were lower in mice treated with the combined therapy, although differences were not significant. Combined LAMB + G-CSF therapy could be a promising approach for the treatment of disseminated infections of S. prolificans, although further studies are required to determine the most appropriate doses.

Topics: Amphotericin B; Animals; Antifungal Agents; Colony Count, Microbial; Disease Models, Animal; Drug Therapy, Combination; Granulocyte Colony-Stimulating Factor; Humans; Immunosuppression Therapy; Liposomes; Male; Mice; Mice, Inbred Strains; Mycoses; Opportunistic Infections; Recombinant Proteins; Scedosporium; Survival Rate

Candida glabrata is the second leading cause of adult candidemia, resulting in high mortality. Amphotericin B is considered the treatment of choice, while the efficacy of fluconazole is controversial and caspofungin efficacy is unknown. To ascertain drug efficacy in vivo, the utility of a murine model of C. glabrata infection was investigated. C. glabrata was found to cause progressive, lethal infection when injected intravenously into C57BL/6 mice with reduced oxidative microbicidal capacity due to knockout of the p47(phox) gene. Spleen and kidney organ CFU counts were determined in groups of mice 2 days after the mice completed 6 days of daily intraperitoneal drug treatment, which began on the day of infection. Daily injections of fluconazole at 80 mg/kg did not reduce spleen or kidney CFU counts after infection with C. glabrata strains having in vitro fluconazole MICs of 2, 32, or 256 microg/ml compared to saline-treated controls. However, this fluconazole regimen reduced spleen CFU counts in mice infected with Candida albicans, an infection that is known to be responsive to fluconazole. Caspofungin at 5 mg/kg and amphotericin B at 5 mg/kg were both effective in reducing fungal burden in spleens and kidneys of C. glabrata-infected mice. Ten mice treated for 6 days with caspofungin at 1 mg/kg survived for 15 days, though all 10 saline-injected mice died or were so ill that they had to be sacrificed by 96 h postinfection. This murine model provided evidence of the efficacy of amphotericin B and caspofungin but not of fluconazole against C. glabrata infection.

Topics: Amphotericin B; Animals; Antifungal Agents; Candida; Candidiasis; Disease Models, Animal; Female; Fluconazole; Humans; Interferon-gamma; Mice; Mice, Inbred C57BL; Mice, Knockout; NADPH Oxidases; Phosphoproteins; Treatment Outcome; Virulence

A new delivery system, Ionic Amphiphilic Biovector (ABV), comprised of anionic lipids (dipalmitoyl phosphatidyl glycerol) included in a cationic cross-linked polysaccharide matrix was used as a reservoir for amphotericin B (AmB). Two ABV formulations exhibited an in vitro and in vivo efficacy similar to commercial AmBisome against Leishmania donovani-infected mice. The higher stability of these ABV formulations indicates their potential for further development and applications.

Topics: Amphotericin B; Animals; Antiprotozoal Agents; Disease Models, Animal; Drug Carriers; Female; Humans; Leishmania donovani; Leishmaniasis, Visceral; Lipids; Mice; Mice, Inbred BALB C; Phosphatidylglycerols; Polysaccharides

In the present study, we report the potential of an immunomodulator tuftsin in increasing the efficacy of liposomised Amphotericin B (Amp B) against drug sensitive as well as drug resistant experimental murine candidiasis. The Amp B containing liposomes demonstrated strong potential of eliminating systemic candidiasis (70% survival) in animals infected with Amp B sensitive strain of Candida albicans (C. albicans). The same liposomal formulation was found to be ineffective in treatment of animals infected with drug resistant C. albicans. However, the co-administration of liposomal formulation of Amp B along with an immunomodulator tuftsin, was found to be competent enough in curing even the drug resistant candidiasis. In contrast, none of the animals survived in the control groups, which were treated with free or liposomised Amp B (without tuftsin). Further, the effect of liposomised tuftsin, on T-cell proliferation as well as antibody production reveals that tuftsin elicits strong immunopotentiating effects as well. The pretreatment with liposomised tuftsin prior to challenging the animals with drug resistant C. albicans infection has also been effective and shows an extra edge in prophylactic perspectives.

Topics: Adjuvants, Immunologic; Amphotericin B; Animals; Antifungal Agents; Antigens; Candida albicans; Candidiasis; Disease Models, Animal; Drug Resistance, Fungal; Drug Synergism; Female; Immunoglobulin G; Kidney; Liposomes; Liver; Lung; Mice; Mice, Inbred BALB C; Ovalbumin; Spleen; T-Lymphocytes; Tuftsin

The outcome of central nervous system (CNS) histoplasmosis is often unfavorable. Although fluconazole plays an integral role in treatment of fungal meningitis, its role in the treatment of histoplasmosis is hampered by reduced activity and potential development of resistance. A murine model of CNS histoplasmosis was used to evaluate the hypothesis that a combination of amphotericin B and fluconazole therapy would be superior to amphotericin B monotherapy. Groups of B6C3F(1) mice were infected by injection of Histoplasma capsulatum into the subarachnoid space. The addition of fluconazole hindered the antifungal effect of amphotericin B, as determined by measurement of fungal burden, suggesting antagonism in the brain. Fluconazole was less effective as a single agent than was amphotericin B, despite the greater penetration of fluconazole into brain tissues. The hypothesis that amphotericin B-fluconazole combination therapy would be superior to amphotericin B monotherapy for treatment of CNS histoplasmosis was not supported by this study.

Topics: Amphotericin B; Animals; Antifungal Agents; Brain; Central Nervous System Fungal Infections; Disease Models, Animal; Drug Therapy, Combination; Female; Fluconazole; Histoplasmosis; Mice; Spleen

With use of a novel model of invasive Aspergillus fumigatus, the efficacy of prophylactic versus therapeutic administration of liposomal amphotericin B (L-AmB) was tested in C57BL/6 mice. After lethal irradiation and transplantation of whole bone marrow (d 0), animals were challenged with conidia either intravenously or via nasal instillation on d +3 and divided into 3 groups: group I received 5% dextrose in water throughout the study period; group II received L-AmB, 5 mg/kg, beginning on d +4; and group III received L-AmB, 5 mg/kg on d -4, d -2, d 0, and d +2, then daily starting d +4. Groups I and II did not survive intravenous challenge, whereas group III had a 40% survival rate. After nasal instillation of conidia, the survival was 25%, 35%, and 85% for mice in groups I, II, and III, respectively. These results demonstrate that prophylactic administration of L-AmB increased early survival against lethal challenge with A. fumigatus, compared with therapy instituted after infection.

Topics: Amphotericin B; Animals; Antibiotic Prophylaxis; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Disease Models, Animal; Disease-Free Survival; Hematopoietic Stem Cell Transplantation; Liposomes; Mice; Mice, Inbred C57BL; Postoperative Complications; Treatment Outcome

The synthesis and biological properties of a novel water-soluble echinocandin-like lipopeptide, FR131535, are described. This compound displayed potent in vitro and in vivo antifungal activities. The hemolytic activity of FR901379 was reduced by replacing the acyl side chain. This compound showed good water-solubility, comparable to the natural product FR901379.

Topics: Animals; Anti-Bacterial Agents; Antifungal Agents; Bronchogenic Cyst; Candida albicans; Candidiasis; Disease Models, Animal; Echinocandins; Female; Fungal Proteins; Glucosyltransferases; Hemolysis; Membrane Proteins; Mice; Mice, Nude; Peptides; Peptides, Cyclic; Pneumonia, Pneumocystis; Schizosaccharomyces pombe Proteins; Solubility

We have previously shown that gamma interferon (IFN-gamma) is a useful adjunct to therapy of experimental systemic cryptococcosis in normal mice. To better emulate AIDS patients, SCID mice were infected intravenously with Cryptococcus neoformans. Mice received no therapy, 3 mg of amphotericin B (AmB) per kg of body weight, or 10(5) U of IFN-gamma alone (prophylactically and therapeutically or only therapeutically) or with AmB. In the first experiment, >75% of the mice survived. Therapy with AmB alone was efficacious compared to no therapy in all organs. Both regimens of IFN-gamma alone were efficacious in the brain and lungs, and the combination of AmB and IFN-gamma showed significant synergy in the kidneys. AmB alone cured 40% of mice of infection, whereas the combination regimens cured >50% of the mice and 90% of the brain infections. In a second study, IFN-gamma again proved efficacious alone, and when given with AmB its efficacy was improved. Therapeutic IFN-gamma alone was effective only in the liver compared to no therapy, and the combination regimen, although highly effective, showed no significant synergy. In a third experiment, AmB alone or in combination with IFN-gamma prolonged survival compared to no therapy or IFN-gamma alone. The combination regimen showed significant synergy over AmB alone in the brain, liver, kidneys, and lungs. AmB alone cured no mice of infections in more than two organs, whereas AmB in combination with IFN-gamma cured 55% of infections in three or more organs. These results indicate that IFN-gamma has therapeutic efficacy in severely immunodeficient animals, especially in combination with AmB. Significant synergistic activity was noted in all organs except the spleen. Overall, IFN-gamma has utility as an adjunctive therapy against systemic cryptococcosis in the severely immunocompromised host.

Topics: Adjuvants, Immunologic; Amphotericin B; Animals; Antifungal Agents; Cryptococcosis; Disease Models, Animal; Drug Therapy, Combination; Interferon-gamma; Male; Mice; Mice, SCID; Recombinant Proteins; Treatment Outcome

In vivo pharmacodynamic parameters have been described for a variety of antibacterials. These parameters have been studied in correlation with in vivo outcomes in order to determine which dosing parameter is predictive of outcome and the magnitude of that parameter associated with efficacy. Very little is known about pharmacodynamics for antifungal agents. We utilized a neutropenic mouse model of disseminated candidiasis to correlate pharmacodynamic parameters (percent time above MIC [T > MIC], area under the concentration time curve [AUC]/MIC ratio, and peak serum level/MIC ratio) for amphotericin B in vivo with efficacy, as measured by organism number in homogenized kidney cultures after 72 h of therapy. Amphotericin B was administered by the intraperitoneal route. Drug kinetics for amphotericin B in infected mice were nonlinear. Serum half-lives ranged from 13 to 27 h. Infection was achieved by intravenous inoculation with 10(6) CFU of yeast cells per ml via the lateral tail vein of neutropenic mice. Groups of mice were treated with fourfold escalating total doses of amphotericin B ranging from 0.08 to 20 mg/kg of body weight divided into 1, 3, or 6 doses over 72 h. Increasing doses produced concentration-dependent killing, ranging from 0 to 2 log(10) CFU/kidney compared to the organism number at the start of therapy. Amphotericin B also produced prolonged dose-dependent suppression of growth after serum levels had fallen below the MIC. Nonlinear regression analysis was used to determine which pharmacodynamic parameter best correlated with efficacy. Peak serum level in relation to the MIC (peak serum level/MIC ratio) was the parameter best predictive of outcome, while the AUC/MIC ratio and T > MIC were only slightly less predictive (peak serum level/MIC ratio, coefficient of determination [R(2)] = 90 to 93%; AUC/MIC ratio, R(2) = 49 to 69%; T > MIC, R(2) = 67 to 85%). The total amount of drug necessary to achieve various microbiological outcomes over the treatment period was 4.8- to 7.6-fold smaller when the dosing schedule called for large single doses than when the same amount of total drug was administered in 2 to 6 doses. Given the narrow therapeutic window of amphotericin B and frequent treatment failures, these results suggest the need for a reevaluation of current dosing regimens.

Topics: Amphotericin B; Animals; Antifungal Agents; Candida albicans; Candidiasis; Colony Count, Microbial; Disease Models, Animal; Female; Mice; Mice, Inbred ICR; Microbial Sensitivity Tests; Neutropenia

The number of cases of systemic histoplasmosis has increased substantially in recent years, and improved therapy is needed. We examined the efficacy of immunomodulation with interferon (IFN)-gamma alone or in combination with a suboptimal regimen of amphotericin B for the treatment of primary systemic murine histoplasmosis. In the first study, BALB/c mice were infected with Histoplasma capsulatum G217B and treated with 10(5) U of IFN given every other day either preinfection and postinfection or only postinfection, alone or in combination with amphotericin B. IFN alone given subcutaneously (s.c.) postinfection prolonged survival over untreated controls (P < 0.01), whereas intravenous (i.v.) administration was ineffective. All combination regimens and amphotericin B alone significantly prolonged survival (P < 0.0001). The combination regimens of amphotericin B and IFN i.v. (pre- and postinfection) or IFN s.c. (postinfection) reduced the fungal burden in the liver and spleen; the latter regimen had superior efficacy in the spleen (P < 0.05) to either amphotericin B or IFN alone. After infection with a low-challenge inoculum, IFN given s.c. (pre- and postinfection) alone caused a significant reduction in fungal burden in the spleen (P < 0.001). In an acutely lethal model, combination regimens of IFN s.c. or i.v. and amphotericin B again prolonged survival (P < 0.01-0.001), with amphotericin B plus IFN given s.c. (pre- and postinfection) superior to all regimens (P < 0.05-0.01). This regimen also showed enhanced efficacy in causing the reduction of fungal burden in the spleen (P < 0.05). These results indicate that IFN in combination with AmB shows enhanced efficacy in the treatment of systemic histoplasmosis and support the potential utility of IFN as an adjunctive therapy.

Topics: Administration, Cutaneous; Amphotericin B; Animals; Antifungal Agents; Carrier Proteins; CASP8 and FADD-Like Apoptosis Regulating Protein; Disease Models, Animal; Drug Therapy, Combination; Histoplasma; Histoplasmosis; Interferon-gamma; Intracellular Signaling Peptides and Proteins; Liver; Mice; Mice, Inbred BALB C; Spleen

We have attempted to validate in Aspergillus flavus the main in vitro methodologies that have been used to detect resistance in Aspergillus fumigatus. We developed a murine model with two A. flavus isolates, one that was apparently resistant in vitro to amphotericin B (AFL5) and another that was resistant to itraconazole (AFL8). No correlation was found for amphotericin B in AFL5, since the in vivo response was compatible with a susceptible isolate. Modification of the in vitro susceptibility test methodology for amphotericin B was unsuccessful. Although AFL8 was apparently resistant to itraconazole in vitro, it was found to be susceptible in vivo. Additional in vitro work has detected weaknesses in the in vitro susceptibility methodology validated for A. fumigatus when applied to A. flavus. The principal problems are that changes in the inoculum have a large effect on the MICs of itraconazole for some A. flavus strains and that a trailing end point and spore sediment often appear when an inoculum with a higher colony count is used. We propose a modified method using a final inoculum of 2.5 x 10(4) CFU per ml of RPMI 1640 medium with 2% glucose buffered to pH 7.0 in a microtiter format, incubated for 48 h with no growth end point. Validation of this methodology requires one or more itraconazole-resistant A. flavus isolates, which have yet to be identified.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus flavus; Disease Models, Animal; Drug Resistance, Microbial; Itraconazole; Male; Mice; Microbial Sensitivity Tests; Statistics as Topic

The activities of amphotericin B and itraconazole were studied in a temporarily neutropenic murine model of disseminated Absidia corymbifera infection, caused by two different strains. Amphotericin B MICs were 0.25 mg/L for both strains and itraconazole MICs were 1 and 2 mg/L. Amphotericin B was effective in vivo with both isolates. Itraconazole was less effective.

Topics: Absidia; Amphotericin B; Animals; Antifungal Agents; Disease Models, Animal; Humans; Itraconazole; Male; Mice; Microbial Sensitivity Tests; Mucormycosis

In experimental visceral leishmaniasis, in which the tissue macrophage is the target, in vivo responsiveness to conventional chemotherapy (pentavalent antimony [Sb]) requires a T-cell-dependent mechanism. To determine if this mechanism involves gamma interferon (IFN-gamma)-induced activation and/or specific IFN-gamma-regulated macrophage leishmanicidal mechanisms (generation of reactive nitrogen or oxygen intermediates, we treated gene-deficient mice infected with Leishmania donovani. In IFN-gamma gene knockout (GKO) mice, Sb inhibited but did not kill intracellular L. donovani (2% killing versus 76% in controls). Sb was active (>94% killing), however, in both inducible nitric oxide synthase (iNOS) knockout (KO) and respiratory burst (phagocyte oxidase)-deficient chronic granulomatous disease (X-CGD) mice. Sb's efficacy was also maintained in doubly deficient animals (X-CGD mice treated with an iNOS inhibitor). In contrast to Sb, amphotericin B (AmB) induced high-level killing in GKO mice; AmB was also fully active in iNOS KO and X-CGD animals. Although resolution of L. donovani infection requires iNOS, residual visceral infection remained largely suppressed in iNOS KO mice treated with Sb or AmB. These results indicate that endogenous IFN-gamma regulates the leishmanicidal response to Sb and achieves this effect via a pathway unrelated to the macrophage's primary microbicidal mechanisms. The role of IFN-gamma is selective, since it is not a cofactor in the response to AmB. Treatment with either Sb or AmB permits an iNOS-independent mechanism to emerge and control residual intracellular L. donovani infection.

Topics: Amphotericin B; Animals; Antimony; Antiprotozoal Agents; Disease Models, Animal; Enzyme Inhibitors; Female; Granulomatous Disease, Chronic; Guanidines; Interferon-gamma; Leishmaniasis, Visceral; Liver; Macrophages; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Nitric Oxide Synthase; Nitric Oxide Synthase Type II

The histopathological response of scrapie-infected hamsters treated at the late stage of the infection with an "anti-scrapie" drug, a polyene macrolide antibiotic designated MS-8209, was evaluated in the brain. The results showed that (1) MS-8209 prolonged significantly the incubation time of the experimental disease, (2) MS-8209 delayed the appearance of spongiosis and astrogliosis in the brain, (3) immunodetection of abnormal prion protein and glial fibrillary acidic protein was significantly reduced in the central nervous system. In addition, this report indicates that polyene antibiotics markedly delay the development of the classical brain lesions that result from scrapie infection.

Topics: Amphotericin B; Animals; Anti-Bacterial Agents; Antiviral Agents; Astrocytes; Blotting, Western; Brain; Cricetinae; Disease Models, Animal; Edema; Female; Glial Fibrillary Acidic Protein; Gliosis; Immunohistochemistry; Mesocricetus; Prions; Scrapie

Amphotericin B has been the standard therapy for invasive aspergillosis since its introduction in 1957. It is only moderately effective. Many susceptibility tests have been used but little variation has been noted between strains. We have studied three strains of Aspergillus fumigatusand one of Aspergillus terreusin a neutropenic mouse model of invasive aspergillosis and attempted to correlate the variable efficacy in vivowith MICs generated by over 30 different susceptibility test formats. One strain of A. fumigatus(AF65) and the strain of A. terreus(AT49) were 'resistant' and the remaining two strains of A. fumigatus(AF210 and AF294) were 'susceptible' in vivo. Only AT49 had elevated MICs of amphotericin (MIC 2 mg/L) by 41 of 54 in vitrotesting systems. With each test format, including Etest, there was no distinction between MICs obtained for AF65, AF210 and AF294 (MICs 0.125-64 mg/L depending on the test). Thus despite extensive efforts we have been unable to correlate susceptible test results with in vivooutcome in A. fumigatusbut we have with A. terreus, with some test formats. This suggests that, at present, amphotericin B susceptibility testing of A. fumigatus is of limited clinical value and further work needs to be done to find testing systems that can identify the 'resistance' documented in vivo.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Disease Models, Animal; Male; Mice; Microbial Sensitivity Tests

SCH56592 (SCH) was evaluated in an immunosuppressed rabbit model of invasive aspergillosis. SCH was more effective than similar doses of itraconazole and as effective as amphotericin B in the clearance of Aspergillus spp. from tissues. Compared with controls, SCH regimens reduced mortality, improved survival, and significantly reduced tissue colony counts.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus; Colony Count, Microbial; Disease Models, Animal; Female; Immunosuppression Therapy; Itraconazole; Microbial Sensitivity Tests; Rabbits; Triazoles

Ramichloridium obovoideum ("Ramichloridium makenziei") is a rare cause of lethal cerebral phaeohyphomycosis. It has been, so far, geographically restricted to the Middle East. BALB/c mice were inoculated with two strains of R. obovoideum intracranially. Therapy with amphotericin B, itraconazole, or the investigational triazole SCH 56592 was conducted for 10 days. Half the mice were monitored for survival and half were killed for determination of the fungal load in brain tissue. Recipients of SCH 56592 had significantly prolonged survival and lower brain fungal burden, and this result was found for mice infected with both of the fungal strains tested. Itraconazole reduced the brain fungal load in mice infected with one strain but not the other, while amphotericin B had no effect on brain fungal concentrations. This study indicates a possible role of SCH 56592 in the treatment of the serious cerebral phaeohyphomycosis due to R. obovoideum.

Topics: Amphotericin B; Animals; Antifungal Agents; Ascomycota; Central Nervous System Fungal Infections; Disease Models, Animal; Female; Itraconazole; Mice; Mice, Inbred BALB C; Mice, Inbred ICR; Mycoses; Triazoles

We compared the efficacies of amphotericin B and voriconazole against invasive pulmonary aspergillosis in a guinea-pig model. A susceptible isolate of Aspergillus fumigatus was used to produce the infection. Voriconazole-treated animals had significantly better survival and decreased fungal burden in the lungs as compared with controls. Although no statistical difference was seen between the efficacies of voriconazole and amphotericin B, a trend favouring voriconazole was noted. Thus, voriconazole, with its cidal activity, may be an attractive alternative to potentially toxic amphotericin B in the treatment of invasive pulmonary aspergillosis.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Disease Models, Animal; Female; Fungemia; Guinea Pigs; Humans; Lung Diseases, Fungal; Microbial Sensitivity Tests; Pyrimidines; Triazoles; Voriconazole

Nikkomycin Z was tested both in vitro and in vivo for efficacy against Histoplasma capsulatum. Twenty clinical isolates were tested for susceptibility to nikkomycin Z in comparison to amphotericin B and itraconazole. The median MIC was 8 microg/ml with a range of 4 to 64 microg/ml for nikkomycin Z, 0.56 microg/ml with a range of 0.5 to 1.0 microg/ml for amphotericin B, and < or =0.019 microg/ml for itraconazole. Primary studies were carried out by using a clinical isolate of H. capsulatum for which the MIC of nikkomycin Z was greater than or equal to 64 microg/ml. In survival experiments, mice treated with amphotericin B at 2.0 mg/kg/dose every other day (QOD) itraconazole at 75 mg/kg/dose twice daily (BID), and nikkomycin Z at 100 mg/kg/dose BID survived to day 14, while 70% of mice receiving nikkomycin Z at 20 mg/kg/dose BID and none of the mice receiving nikkomycin Z at 5 mg/kg/dose BID survived to day 14. All vehicle control mice died by day 12. Fungal burden was assessed on survivors. Mice treated with nikkomycin Z at 20 and 100 mg/kg/dose BID had significantly higher CFUs per gram of organ weight in quantitative cultures and higher levels of Histoplasma antigen in lung and spleen homogenates than mice treated with amphotericin B at 2.0 mg/kg/dose QOD or itraconazole at 75 mg/kg/dose BID. Studies also were carried out with a clinical isolate for which the MIC of nikkomycin Z was 4 microg/ml. All mice treated with amphotericin B at 2.0 mg/kg/dose QOD; itraconazole at 75 mg/kg/dose BID; and nikkomycin Z at 100, 20, and 5 mg/kg/dose BID survived until the end of the study at day 17 postinfection, while 30% of the untreated vehicle control mice survived. Fungal burden assessed on survivors showed similar levels of Histoplasma antigen in lung and spleen homogenates of mice treated with amphotericin B at 2.0 mg/kg/dose QOD; itraconazole at 75 mg/kg/dose BID; and nikkomycin Z at 100, 20, and 5 mg/kg/dose BID. The three surviving vehicle control mice had significantly higher antigen levels in lung and spleen than other groups (P<0.05). The efficacy of nikkomycin Z at preventing mortality and reducing fungal burden correlates with in vitro susceptibility.

Topics: Aminoglycosides; Amphotericin B; Animals; Anti-Bacterial Agents; Antifungal Agents; Cells, Cultured; Disease Models, Animal; Histoplasmosis; Itraconazole; Mice

Twenty clinical isolates of Histoplasma capsulatum were tested for their in vitro susceptibilities to caspofungin in comparison to those to amphotericin B by following National Committee for Clinical Laboratory Standards guidelines for yeasts. The mean MICs were 16.6 microgram/ml (range, 8 to 32 microgram/ml) for caspofungin and 0.56 microgram/ml (range, 0.5 to 1.0 microgram/ml) for amphotericin B. Survival experiments used a 10(5) dose in a pulmonary challenge model with B6C3F(1) mice. All mice that received amphotericin B at 2 mg/kg of body weight every other day (q.o.d.), 30% of mice that received caspofungin at 8 mg/kg/day, and 20% of mice that received caspofungin at 4 mg/kg/day survived to day 15, while mice that received caspofungin at 2 mg/kg/day and all control mice that received the vehicle died by day 14. Amphotericin B at 2 mg/kg q.o.d. markedly reduced the fungal burden in the lungs and spleens, as measured by Histoplasma antigen detection techniques and quantitative cultures, for each comparison. Caspofungin at 10 mg/kg twice a day (b.i.d.) did not reduce the fungal burden, as measured by antigen detection techniques, but slightly reduced the levels of fungi in both the lungs and spleens, as determined by quantitative cultures. Caspofungin at 5 mg/kg b.i.d. did not affect fungal burden. Overall, caspofungin had only a slight effect on survival or fungal burden.

Topics: Amphotericin B; Animals; Anti-Bacterial Agents; Antifungal Agents; Caspofungin; Disease Models, Animal; Echinocandins; Histoplasma; Histoplasmosis; Humans; Lipopeptides; Mice; Microbial Sensitivity Tests; Peptides; Peptides, Cyclic; Treatment Outcome

The in-vivo activity of amphotericin B and itraconazole against a clinical isolate of Aspergillus terreus was determined in a murine model of disseminated aspergillosis. MICs of amphotericin B and itraconazole for the strain, determined by an NCCLS-based technique, were 2 microg/ml and 1 microg/ml, respectively. Mice infected intravenously were treated with either itraconazole (50 or 100 mg/kg/day) or amphotericin B 4.5 mg/kg/day for 10 days. Treatment with both doses of itraconazole significantly prolonged the survival rates compared with those for untreated mice. In comparison, mortality rate and median survival time were identical for mice treated with amphotericin B and for mice given no therapy, indicating that the strain was highly resistant to amphotericin B in this model. Analysis of sterol composition showed that the major sterol was ergosterol. This suggests that amphotericin B resistance was not related to a modified sterol profile.

Topics: Amphotericin B; Animals; Aspergillosis; Aspergillus; Brain; Disease Models, Animal; Drug Resistance, Microbial; Humans; Itraconazole; Kidney; Lung Diseases, Fungal; Mice; Microbial Sensitivity Tests; Middle Aged; Sterols

The central nervous system (CNS) distribution and antifungal efficacy of all 4 approved formulations of amphotericin B (AmB) were investigated in a rabbit model of hematogenous Candida albicans meningoencephalitis. Treatment with AmB deoxycholate (1 mg/kg/day) or liposomal AmB (5 mg/kg/day) yielded the highest peak plasma concentration (C(max)), area under concentration versus time curve from zero to 24 h (AUC(0-24)), and time during dosing level tau Ttau>minimum inhibitory complex (MIC) values and led to complete eradication of C. albicans from brain tissue (P<.05 vs. untreated controls). By comparison, AmB colloidal dispersion and AmB lipid complex (5 mg/kg/day each) were only partially effective (not significant vs. untreated controls). There was a strong correlation of C(max), AUC(0-24), C(max)/MIC, AUC(0-24)/MIC, and Ttau>MIC with clearance of C. albicans from brain tissue (P

Topics: Amphotericin B; Animals; Antifungal Agents; Candida albicans; Candidiasis; Central Nervous System Fungal Infections; Chemistry, Pharmaceutical; Disease Models, Animal; Drug Delivery Systems; Female; Lipids; Microbial Sensitivity Tests; Rabbits; Treatment Outcome

AmBisome is a liposomal formulation of amphotericin B that has broad-spectrum antifungal activity and greatly reduced toxicity compared to the parent drug. In this study, amphotericin B deoxycholate (Fungizone) (1 mg/kg) and AmBisome (1 to 20 mg/kg) were tested as single-dose prophylactic agents in both immunocompetent and immunosuppressed C57BL/6 mice challenged with either Candida albicans or Histoplasma capsulatum. Prophylactic efficacy was based on survival and fungal burden in the target organ (kidneys or spleen). At 9 to 10 days after histoplasma challenge, 80 to 90% of both immunocompetent and immunosuppressed mice in the control and Fungizone groups had died. All AmBisome-treated mice survived, although in the AmBisome groups given 1 mg/kg, the mice became moribund by day 10 to 12. No spleen CFU were detected in the histoplasma-challenged mice given 10 or 20 mg of AmBisome per kg. By 23 to 24 days after histoplasma challenge, fungal growth and/or death had occurred in all immunosuppressed mice except for four mice receiving 20 mg of AmBisome per kg. There were still no detectable fungi in the spleens of immunocompetent mice given 10 or 20 mg of AmBisome per kg. In the C. albicans experiment at 7 days postchallenge, all animals in both untreated and treated groups were alive with culture-positive kidneys. The kidney fungal burdens in AmBisome groups given 5 to 20 mg/kg were at least 1 log unit lower than those in the Fungizone group and significantly lower than those in the untreated control group (P < 0.05). There was a trend toward decreasing fungal growth in the kidneys as the dose of AmBisome was increased. In conclusion, these results show that a single high dose of AmBisome (5 to 20 mg/kg) had prophylactic efficacy in immunocompetent and immunosuppressed murine H. capsulatum and C. albicans models.

Topics: Amphotericin B; Animals; Antibiotic Prophylaxis; Antifungal Agents; Candida albicans; Candidiasis; Disease Models, Animal; Female; Histoplasma; Histoplasmosis; Immunocompetence; Immunocompromised Host; Kidney; Mice; Mice, Inbred C57BL; Spleen; Stem Cells

Amphotericin B (AMB) remains the principal therapeutic choice for deep mycoses. However, its application is limited by toxicity and a route of administration requiring slow intravenous injection. An oral formulation of this drug is desirable to treat acute infections and provide prophylactic therapy for high-risk patients. Cochleates are a novel lipid-based delivery system that have the potential for oral administration of hydrophobic drugs. They are stable phospholipid-cation crystalline structures consisting of a spiral lipid bilayer sheet with no internal aqueous space. Cochleates containing AMB (CAMB) inhibit the growth of Candida albicans, and the in vivo therapeutic efficacy of CAMB administered orally was evaluated in a mouse model of systemic candidiasis. The results indicate that 100% of the mice treated at all CAMB doses, including a low dosage of 0.5 mg/kg of body weight/day, survived the experimental period (16 days). In contrast, 100% mortality was observed with untreated mice by day 12. The fungal tissue burden in kidneys and lungs was assessed in parallel, and a dose-dependent reduction in C. albicans from the kidneys was observed, with a maximum 3.5-log reduction in total cell counts at 2.5 mg/kg/day. However, complete clearance of the organism from the lungs, resulting in more than a 4-log reduction, was observed at the same dose. These results were comparable to a deoxycholate AMB formulation administered intraperitoneally at 2 mg/kg/day (P < 0.05). Overall, these data demonstrate that cochleates are an effective oral delivery system for AMB in a model of systemic candidiasis.

Topics: Administration, Oral; Amphotericin B; Animals; Antifungal Agents; Candidiasis; Chemistry, Pharmaceutical; Delayed-Action Preparations; Disease Models, Animal; Drug Carriers; Drug Delivery Systems; Female; Kidney; Lung; Mice; Mice, Inbred BALB C; Treatment Outcome

The interaction of amphotericin B (AmB) and azole antifungal agents in the treatment of fungal infections is still a controversial issue. A checkerboard titration broth microdilution-based method that adhered to the recommendations of the National Committee for Clinical Laboratory Standards was applied to study the in vitro interactions of AmB with fluconazole (FLC), itraconazole (ITC), and the new investigational triazole SCH 56592 (SCH) against 15 clinical isolates of Cryptococcus neoformans. Synergy, defined as a fractional inhibitory concentration (FIC) index of < or =0.50, was observed for 7% of the isolates in studies of the interactions of both FLC-AmB and ITC-AmB and for 33% of the isolates in studies of the SCH-AmB interactions; additivism (FICs, >0.50 to 1.0) was observed for 67, 73, and 53% of the isolates in studies of the FLC-AmB, ITC-AmB, and SCH-AmB interactions, respectively; indifference (FICs, >1.0 to < or =2.0) was observed for 26, 20, and 14% of the isolates in studies of the FLC-AmB, ITC-AmB, and SCH-AmB interactions, respectively. Antagonism (FIC >2.0) was not observed. When synergy was not achieved, there was still a decrease, although not as dramatic, in the MIC of one or both drugs when they were used in combination. To investigate the effects of FLC-AmB combination therapy in vivo, we established an experimental model of systemic cryptococcosis in BALB/c mice by intravenous injection of cells of C. neoformans 2337, a clinical isolate belonging to serotype D against which the combination of FLC and AmB yielded an additive interaction in vitro. Both survival and tissue burden studies showed that combination therapy was more effective than FLC alone and that combination therapy was at least as effective as AmB given as a single drug. On the other hand, when cells of C. neoformans 2337 were grown in FLC-containing medium, a pronounced increase in resistance to subsequent exposures to AmB was observed. In particular, killing experiments conducted with nonreplicating cells showed that preexposure to FLC abolished the fungicidal activity of the polyene. However, this apparent antagonism was not observed in vivo. Rather, when the two drugs were used sequentially for the treatment of systemic murine cryptococcosis, a reciprocal potentiation was often observed. Our study shows that (i) the combination of triazoles and AmB is significantly more active than either drug alone against C. neoformans in vitro and (ii) the concomitant or sequenti

Topics: Amphotericin B; Animals; Antifungal Agents; Cryptococcosis; Cryptococcus neoformans; Disease Models, Animal; Drug Therapy, Combination; Fluconazole; Humans; Itraconazole; Male; Mice; Mice, Inbred BALB C; Microbial Sensitivity Tests; Triazoles

The need for new therapies to treat systemic fungal infections continues to rise. Naturally occurring hexapeptide echinocandin B (1) has shown potent antifungal activity via its inhibition of the synthesis of beta-1,3 glucan, a key fungal cell wall component. Although this series of agents has been limited thus far based on their physicochemical characteristics, we have found that the synthesis of analogues bearing an aminoproline residue in the 'northwest' position imparts greatly improved water solubility (> 5 mg/mL). The synthesis and structure-activity relationships (SAR) based on whole cell and upon in vivo activity of the series of compounds are reported.

Topics: Acute Disease; Amines; Amphotericin B; Animals; Anti-Bacterial Agents; Antifungal Agents; Candida; Candidiasis, Vulvovaginal; Disease Models, Animal; Dose-Response Relationship, Drug; Echinocandins; Female; Fungal Proteins; Mice; Microbial Sensitivity Tests; Peptides; Peptides, Cyclic; Proline; Solubility; Structure-Activity Relationship; Yeasts

The possible enhancement, using immunotherapy with interferon-gamma (IFN-gamma), combined with conventional antifungal therapy, was studied in a murine model of systemic cryptococcosis. Four weeks after intravenous challenge, infection was quantified in brains and livers of survivors. Groups received IFN-gamma every other day beginning 7 days before (prophylaxis), or after infection (14 doses), or amphotericin B post-infection, or combinations of these regimens. IFN-gamma alone was modestly effective, but impressively and significantly potentiated amphotericin in reducing infection in the most important site of infection, the brain. The efficacy was seen after lethal and non-lethal challenges, and when IFN-gamma was given by the intravenous or subcutaneous routes. In non-lethal infection, only the combination amphotericin-IFN-gamma resulted in sterilization of the central nervous system. Potentiation of fluconazole was less impressive. Adding prophylactic IFN-gamma doses to IFN-gamma therapy did not consistently enhance the therapeutic effect. These results suggest IFN-gamma may have a role in potentiating conventional antifungal therapy of cryptococcosis.

Topics: Amphotericin B; Animals; Antifungal Agents; Brain; Colony Count, Microbial; Cryptococcosis; Cryptococcus neoformans; Disease Models, Animal; Drug Synergism; Drug Therapy, Combination; Fluconazole; Humans; Interferon-gamma; Liver; Male; Mice; Mice, Inbred BALB C

A small animal model of localised candidiasis is needed for the evaluation of new antifungal compounds. Mammary glands of immunocompetent (BALB/cJ) and immunodeficient (SCID and athymic nude) mice were infected with a wild-type of Candida albicans. Some of the animals were treated with amphotericin B (AmB) while others were treated with saline and acted as controls. The histologic changes of infected mammary gland tissues and a number of other organs were evaluated. Complement (C) activation was analysed by immunoelectrophoretic quantification of molecules with C3c epitopes (C3, C3b, iC3b, and C3c) in serum. In all animals the organisms were confined to the mammary glands. Serum C3c levels were significantly higher (P<0.05) in infected untreated BALB/cJ and SCID mice, which also had severe mammary gland tissue inflammation, compared with control mice treated with AmB (4 mg kg(-1) i.p. once daily for 4 days). Both treated and control nude mice showed less tissue inflammation compared to BALB/cJ and SCID mice, and revealed insignificant activation of the complement system. It is concluded that innate immune response is important in the control of candidiasis and that the murine mastitis model is useful for immunopathological studies as well as evaluation of potential antifungal compounds.

Topics: Amphotericin B; Animals; Antifungal Agents; Breast; Candida albicans; Candidiasis; Complement Activation; Complement C3c; Disease Models, Animal; Female; Immunocompetence; Male; Mastitis; Mice; Mice, Inbred BALB C; Mice, Nude; Mice, SCID

A murine model of intratracheally induced histoplasmosis was used to evaluate a new triazole antifungal agent, Schering (SCH) 56592, for treatment of histoplasmosis. MICs were determined for SCH 56592, amphotericin B, and itraconazole by testing yeast-phase isolates from 20 patients by a macrobroth dilution method. The MICs at which 90% of the isolates are inhibited were for 0.019 microgram/ml for SCH 56592, 0.5 microgram/ml for amphotericin B, and < or = 0.019 microgram/ml for itraconazole. Survival studies were done on groups of 10 B6C3F1 mice with a lethal inoculum of 10(5). All mice receiving 5, 1, or 0.25 mg of SCH 56592 per kg of body weight per day, 2.5 mg of amphotericin B per kg every other day (qod), or 75 mg of itraconazole per kg per day survived to day 29. Only 44% of mice receiving 5 mg of itraconazole/kg/day survived to day 29. Fungal burden studies done in similar groups of mice with a sublethal inoculum of 10(4) showed a reduction in CFUs and Histoplasma antigen levels in lung and spleen tissue in animals treated with 2 mg of amphotericin B/kg qod, 1 mg of SCH 56592/kg/day, and 75 mg of itraconazole/kg/day, but not in those treated with lower doses of the study drugs (0.2 mg of amphotericin B/kg qod, 0.1 mg of SCH 56592/kg/day, or 10 mg of itraconazole/kg/day). Serum drug concentrations were measured 3 and 24 h after the last dose in mice (groups of five to seven mice), each treated for 7 days with SCH 56592 (10 and 1 mg/kg/day) and itraconazole (75 and 10 mg/kg/day). Mean levels measured by bioassay were as follows: SCH 56592, 10 mg/kg/day (2.15 micrograms/ml at 3 h and 0.35 microgram/ml at 24 h); SCH 56592, 1 mg/kg/day (0.54 microgram/ml at 3 h and none detected at 24 h); itraconazole, 75 mg/kg/day (22.53 micrograms/ml at 3 h and none detected at 24 h); itraconazole, 10 mg/kg/day (1.33 micrograms/ml at 3 h and none detected at 24 h). Confirmatory results were obtained by high-pressure liquid chromatography assay. These studies show SCH 56592 to be a promising candidate for studies of treatment of histoplasmosis in humans.

Topics: Amphotericin B; Animals; Antifungal Agents; Disease Models, Animal; Histoplasma; Histoplasmosis; Immunocompetence; Itraconazole; Mice; Microbial Sensitivity Tests; Triazoles

Voriconazole (UK-109,496) is a new triazole with in vitro activity against a wide spectrum of fungi including yeasts intrinsically resistant to fluconazole such as Candida krusei. In this study the efficacy of voriconazole was compared to amphotericin B and fluconazole in a neutropenic guinea pig model of hematogenously disseminated C. krusei infection. In guinea pigs, neutropenia was established by using cyclophosphamide (intraperitoneally, i.p., 100 mg/kg on day 1 and 4), and dexamethasone (orally, 2 mg/kg/day, for 8 days). Neutropenic guinea pigs were infected with 0.5 ml of yeast cell suspension (1 x 10(8) CFU) intravenously. Challenged animals were treated with antifungals starting 1 h postinfection for 7 days. The animals were divided into five groups: untreated control, amphotericin B (1 mg/kg i.p. on alternate days), fluconazole (20 mg/kg orally twice daily), and voriconazole (two groups: 5 and 10 mg/kg orally twice daily) groups. Guinea pigs were sacrificed 1 day after the last treatment. Brain, liver, and kidneys were removed and weighed, tissues were homogenized and fungal burden determined by serial quantitative counts. Voriconazole at dosages of 5 or 10 mg/kg b.i.d. was shown to be significantly more efficacious than either amphotericin B or fluconazole in eradicating C. krusei from brain, liver and kidney tissue. These data indicate that voriconazole could be efficacious for the treatment of infections caused by fluconazole-resistant Candida, such as C. krusei.

Topics: Amphotericin B; Animals; Antifungal Agents; Candida; Candidiasis; Disease Models, Animal; Drug Resistance, Microbial; Fluconazole; Guinea Pigs; Male; Neutropenia; Pyrimidines; Random Allocation; Triazoles; Voriconazole

The activity of liposomal nystatin (L-Nys) against subacute disseminated candidiasis was investigated in persistently neutropenic rabbits. Antifungal therapy was administered for 10 days starting 24 h after intravenous inoculation of 10(3) blastoconidia of Candida albicans. Responses to treatment were assessed by the quantitative clearance of the organism from blood and tissues. Treatments consisted of L-Nys at dosages of 2 and 4 mg/kg of body weight/day (L-Nys2 and L-Nys4, respectively) amphotericin B deoxycholate at 1 mg/kg/day (D-AmB), and fluconazole at 10 mg/kg/day (Flu). All treatments were given intravenously once daily. Compared to the results for untreated but infected control animals, treatment with L-Nys2, L-Nys4, D-AmB, and Flu resulted in a significant clearance of the residual burden of C. albicans from the kidney, liver, spleen, lung, and brain (P < 0.0001 by analysis of variance). When the proportion of animals infected at at least one of the five tissue sites studied was evaluated, a dose-dependent response to treatment with L-Nys was found (P < 0.05). Compared to D-AmB-treated rabbits, mean serum creatinine and blood urea nitrogen levels at the end of therapy were significantly lower in animals treated with L-Nys2 (P < 0.001) and L-Nys4 (P < 0.001 and P < 0.01, respectively). L-Nys was less nephrotoxic than conventional amphotericin B and had dose-dependent activity comparable to that of amphotericin B for the early treatment of subacute disseminated candidiasis in persistently neutropenic rabbits.

Topics: Amphotericin B; Animals; Antifungal Agents; Candidiasis; Disease Models, Animal; Drug Carriers; Fluconazole; Liposomes; Nystatin; Rabbits; Treatment Outcome

The immune response against Aspergillus fumigatus has been studied during infection and therapy in order to understand the mechanism of pathogenesis and the effect of treatment with amphotericin B. With this in view an animal model of aspergillosis was developed in Balb/c mice by intravenous injection of an optimized dose of 3. 6x10(6) A. fumigatus spores. Infection due to Aspergillus was well established by histopathological examination and fungal load in the animal. Lesions and eosinophil infiltration was observed in the infected tissues which indicated the involvement of a Type I hypersensitivity response. Evaluation of serological parameters indicated high levels of interleukin-4 (IL-4) and A. fumigatus specific IgG antibodies. The reduction in fungal load and modulation of immune response in the infected mice was studied following treatment with amphotericin B/cholesterol hemisuccinate vesicles (ABCV). The results clearly indicated significant reduction in the fungal load, disappearance of eosinophils and lesions with the appearance of macrophages and neutrophils in the infected lung tissue, a decrease in IL-4 (fourfold) and a concomitant increase of interferon-gamma (IFN-gamma; twofold) with an improvement in general condition of mice. In the non-treated mice, the rise of IL-4 level indicated the association of T(H)2 cell response with susceptibility to infection while the increase of IFN-gamma in the treated group suggested that T(H)1 cell response may be involved in resistance to Aspergillus infection.

Topics: Amphotericin B; Animals; Antibodies, Fungal; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Cholesterol; Cytokines; Disease Models, Animal; Drug Compounding; Erythrocytes; Hemolysis; Immunoglobulin G; Lung; Male; Mice; Mice, Inbred BALB C; Rabbits; Survival Analysis; Th1 Cells; Th2 Cells

An animal model of disseminated aspergillosis was used to test the in-vivo activity of itraconazole against four isolates of Aspergillus fumigatus. Two reference isolates of A. fumigatus known to be resistant to itraconazole in vitro and in vivo were used as control isolates, and two new isolates were tested under the same conditions. For each isolate MICs for itraconazole and amphotericin B were determined by an NCCLS-based method. Mice infected intravenously were treated either with itraconazole 100 mg/ kg/day or amphotericin B 4.5 mg/kg/day for 10 days. Amphotericin B showed good in-vivo activity against all four isolates. For one strain, which had a low in-vitro MIC for itraconazole, in-vivo therapy with itraconazole prolonged the survival of mice and reduced fungal burdens in organs compared with untreated controls. In mice infected with a strain with a high MIC of >16 mg/L, itraconazole neither prolonged survival nor reduced fungal load in organs compared with controls. It is concluded that there is a relationship between MIC and treatment outcome in mice for A. fumigatus infection.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Brain; Colony Count, Microbial; Disease Models, Animal; Drug Resistance, Microbial; Female; Itraconazole; Kidney; Mice; Microbial Sensitivity Tests

Nine isolates of filamentous fungi previously tested in 11 different laboratories for their susceptibilities to amphotericin B and itraconazole in vitro were injected intravenously into mice and guinea pigs, and responses to treatment with both agents were studied. The experiments were done in a single laboratory. Mean survival times, the percentages of animals surviving 12 days after infection, and culture results for samples of deep organs obtained postmortem were used as markers of antifungal efficacy. Because of variations in organism pathogenicity, interpretable test systems in vivo could not be established for Fusarium spp. in mice or guinea pigs or for Pseudallescheria boydii in mice, even with the use of immunosuppressive pretreatments. Among the infections that could be evaluated, some degree of response to the corresponding treatment in vivo was seen in animals infected with each of two Rhizopus arrhizus isolates susceptible to amphotericin B at < 0.5 microg/ml and Aspergillus spp. isolates susceptible to itraconazole at < 1.0 microg/ml. Conversely, no responses were apparent with infecting strains for which MICs were > or = 2 microg/ml (amphotericin B) or > or = 1 microg/ml (itraconazole). However, the limitations of the intravenous challenge systems studied mean that no firm conclusion relating MICs in vitro to the lowest effective doses in vivo could be drawn.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus; Disease Models, Animal; Fusarium; Guinea Pigs; Itraconazole; Mice; Microbial Sensitivity Tests; Mycetoma; Pseudallescheria; Statistics as Topic; Treatment Outcome

The interactions of amphotericin B and itraconazole were studied in murine invasive candidiasis. Candida albicans-infected mice were treated for 10 consecutive days, 24 h after infection. Survival was monitored over 30 days and kidney cultures were done. Mice treated with amphotericin B (0.2 mg/kg/day intraperitoneally) or itraconazole (100 mg/kg/day by oral gavage in two divided doses/ day) had a 30-day survival of 20% or 40%. Concomitant administration of both drugs resulted in 100% mortality; 90% of mice treated with amphotericin B (1 mg/kg/day) survived. With the combination, 100% were dead by day 28 (P < or = .001 vs. amphotericin B). With sequential therapy (i.e., 5 days with one drug and then 5 days with the other), survival was inferior to that with amphotericin B alone but similar to that with itraconazole alone. Kidney culture results confirmed the antagonism of the combination compared with amphotericin B alone. In treatment of murine invasive candidiasis, the concomitant or sequential use of amphotericin B and itraconazole results in a negative interaction.

Topics: Amphotericin B; Animals; Candidiasis; Disease Models, Animal; Drug Antagonism; Drug Therapy, Combination; Itraconazole; Mice; Mice, Inbred ICR

Liver and spleen volumes and serum concentrations of nitrate (the end-product of NO in vivo), albumin, gamma-globulin, protein, creatine and urea were measured during the course of progressive infections with Leishmania infantum MON-1 (MHOM/PR/93/CRE29) in 10 Syrian golden hamsters. Each hamster was infected by intraperitoneal injection with 4 x 10(7) promastigotes. Five of the infected animals were treated, with 6 mg liposomal amphotericin B (L-AmB)/kg given by intracardiac injection, on day 107 post-infection (p.i.). Compared with those in the uninfected hamsters used as controls, the liver volumes in the infected animals became significantly enlarged by day 40 p.i. (38% larger than the controls; P < 0.001) whereas significant enlargement of the spleen was first detected on day 72. Each infected animal had detectable serum levels of antileishmanial antibodies on day 72. There were significant elevations in gamma-globulin concentration as early as day 40 (P < 0.05) but significant falls in albumin concentrations were only detected from day 107 (P < 0.001). Nitrate, creatinine and urea concentrations remained unchanged during the course of infection, even after L-AmB treatment. Serum nitrate levels were not enhanced by L. infantum infection nor by the L-AmB treatment which induced a 98.2% decrease in parasite burden. The lack of NO production in visceral leishmaniasis, with or without L-AmB treatment, points to the unresponsiveness of inducible nitric oxide synthase in this rodent model.

Topics: Amphotericin B; Animals; Antiprotozoal Agents; BCG Vaccine; Cricetinae; Disease Models, Animal; Leishmania infantum; Leishmaniasis, Visceral; Male; Mesocricetus; Nitric Oxide; Nitric Oxide Synthase; Nitric Oxide Synthase Type II

A murine model of disseminated candidiasis involving intranasal challenge with Candida albicans was developed and used to explore the role of C. albicans aspartic proteases as virulence factors during early dissemination. Pretreatment of neutropenic mice with the aspartic protease inhibitor pepstatin A by intraperitoneal injection afforded strong dose-dependent protection against a subsequent lethal intranasal dose of an aspartic protease-producing strain (ATCC 32354) of C. albicans. Administration of 0.6 mg of pepstatin A kg of body weight(-1) prior to challenge and on days 1 to 4 postchallenge resulted in 100% survival at day 15 postchallenge, whereas 100% of animals receiving saline had died by day 6. This effect was comparable to the dose-dependent protection obtained with amphotericin B, which resulted in 100% survival when administered at 0.1 mg kg(-1). The reduction in mortality afforded by pepstatin A correlated with its dose-dependent blockade of C. albicans numbers in the lungs, liver, and kidneys. By sharp contrast, no protection by pepstatin A was observed in mice challenged intravenously, and protection was markedly attenuated in mice given pepstatin A after intranasal challenge only. These data show the utility of pepstatin A in the prophylaxis of disseminated Candida infections and suggest that Candida aspartic proteases play an essential role early in dissemination.

Topics: Administration, Intranasal; Amphotericin B; Animals; Aspartic Acid Endopeptidases; Candida albicans; Candidiasis; Disease Models, Animal; Epithelium; Female; Mice; Pepstatins

Amphotericin B's (Amp B) usefulness is associated with a number of toxic cellular side effects. We investigated the in vivo effects of Amp B on the lipid peroxide (malondialdehyde [MDA]) levels in various organs of rats infused with 1.5 mg/kg body weight of Amp B. The rats (n = 8) experienced cardiac arrest following Amp B infusion. Among the organs, the kidney exhibited higher levels of MDA and was followed by brain > liver > lung > heart. Pretreatment of rats with 0.35 g/kg body weight of fructose-1,6-diphosphate (FDP) prior to Amp B infusion reduced the extent of MDA formation in all organs. These studies suggest that Amp B-associated toxicity in rats may involve the formation of lipid peroxide damage and FDP, in part by reducing these effects, may afford partial protection.

Topics: Amphotericin B; Animals; Anti-Bacterial Agents; Brain; Disease Models, Animal; Fructosediphosphates; Heart; Heart Arrest; Immunologic Factors; Kidney; Lipid Peroxidation; Liver; Lung; Male; Malondialdehyde; Myocardium; Rats; Rats, Sprague-Dawley

Although there are an increasing number of new antifungal agents available, the morbidity and mortality due to invasive mycoses remain high. The high rates of polyene toxicities and the development of azole resistance have raised the issue of using antifungal agents of these classes in combination, despite theoretical concerns regarding antagonism between such agents. This study was designed to evaluate the in vivo efficacy of combined therapy with amphotericin B and fluconazole against Candida albicans. Two distinct animal models were used in this study: a neutropenic-mouse model of hematogenously disseminated candidiasis and the infective-endocarditis rabbit model. Treatment efficacy was assessed by determining reductions in mortality as well as decreases in tissue fungal densities. In the neutropenic-mouse model, amphotericin B, as well as combination therapy, significantly prolonged survival compared to untreated controls (P < 10(-5) and P = 0.001, respectively). The fungal densities in the kidneys of neutropenic mice were significantly reduced with either amphotericin B monotherapy or amphotericin B-fluconazole combined therapy compared to those of controls (P < 10(-6)). Fluconazole monotherapy also reduced fungal densities in the kidneys; however, this decrease was not statistically significant (P = 0.17). In contrast, treatment with either fluconazole alone or combined with amphotericin B (but not amphotericin B monotherapy) significantly decreased fungal densities in the brain (P = 0.025). In the rabbit endocarditis model, amphotericin B monotherapy or combined therapy significantly decreased fungal densities in cardiac vegetations (P < 0.01 versus the controls). Although no significant antagonism was seen when fluconazole was given in combination with amphotericin B, combination therapy did not augment the antifungal activity of amphotericin B.

Topics: Amphotericin B; Animals; Antifungal Agents; Candida albicans; Candidiasis; Disease Models, Animal; Drug Synergism; Drug Therapy, Combination; Endocarditis; Female; Fluconazole; Male; Mice; Mice, Inbred BALB C; Neutropenia; Rabbits

Nikkomycin Z is a chitin synthetase inhibitor. In vitro, nikkomycin Z had good activity against Blastomyces dermatitidis, with an MIC of 0.78 microg/ml and a minimal fungicidal concentration of 3.1 microg/ml. The efficacies of various treatment durations (3, 5, or 10 days) and doses (200, 400, or 1,000 mg/kg of body weight) of nikkomycin Z given twice daily were compared with those of itraconazole at 200 mg/kg given twice daily and amphotericin B at 6.25 mg/kg in a murine model of pulmonary blastomycosis. All treatments prolonged survival compared with untreated controls (P < 0.05 to 0.01); 100% survival was achieved with 5 or 10 days of any nikkomycin Z dose or with amphotericin B. Amphotericin B and nikkomycin Z, but not itraconazole, reduced infection compared with controls. Amphotericin B and the 10-day regimens of all nikkomycin Z doses were equivalent and superior to itraconazole or nikkomycin Z for < or = 5 days at any dose (P < 0.05 to 0.01). Increased duration and/or dosage improved the efficacy of nikkomycin Z, with 10 days of each dose curing 50 to 90% of the animals. Only a 1,000-mg/kg/day dose of nikkomycin Z was curative when treatment lasted less than 10 days. In contrast, itraconazole cured no mice, while amphotericin B cured all mice. Based on the total amount of drug given, amphotericin B was estimated to be 32 times as active as nikkomycin Z and nikkomycin Z was estimated to be 3 times as active as itraconazole. Overall, nikkomycin Z given orally was well tolerated, had good activity against blastomycosis, and could result in biological cure, thus producing results equivalent to those of parenteral amphotericin B.

Topics: Aminoglycosides; Amphotericin B; Animals; Anti-Bacterial Agents; Antifungal Agents; Blastomycosis; Chitin Synthase; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Administration Schedule; Enzyme Inhibitors; Itraconazole; Lung Diseases, Fungal; Male; Mice; Mice, Inbred Strains

To evaluate and compare in vivo the protective efficacy of unilamellar liposomal amphotericin B (L-AmB) with that of deoxycholate amphotericin B (D-AmB) in experimental endocarditis.. In the rabbit model of experimental Aspergillus fumigatus endocarditis, two doses of each antifungal agent (1.5 mg/kg each) were administered intravenously at 4 hours and at 30 minutes before challenge with an inoculum of A. fumigatus. Three days later, the animals were sacrificed, and the aortic vegetations were analyzed.. All 19 animals that did not receive chemoprophylaxis acquired endocarditis. In contrast, endocarditis developed in 2 of 10 animals pretreated with D-AmB (P < 0.01) and 3 of 8 animals pretreated with L-AmB (P < 0.01). Both D-AmB and L-AmB prevented the development of endocarditis due to A. fumigatus and decreased the concentration of fungi in the aortic vegetations by more than 1 log10.. In the rabbit experimental model of Aspergillus endocarditis, D-AmB and L-AmB were equally effective in reducing the incidence of the infection and the tissue burden of fungi.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Cholagogues and Choleretics; Deoxycholic Acid; Disease Models, Animal; Endocarditis; In Vitro Techniques; Liposomes; Male; Rabbits

The efficacy of AmBisome, a liposomal formulation of amphotericin B, was compared with that of Fungizone (amphotericin B desoxycholate), in a rat model of unilateral, pulmonary aspergillosis. Repeated administration of cyclophosphamide resulted in persistent, severe granulocytopenia. The left lung was inoculated with a conidial suspension of Aspergillus fumigatus, thus establishing an unilateral infection. Antifungal treatment was started 40 h after fungal inoculation, at which time mycelial disease was confirmed by histological examination. Both Fungizone 1 mg/kg and AmBisome 10 mg/kg resulted in increased survival in terms of delayed as well as reduced mortality. Quantitative cultures of lung tissue showed that only AmBisome 10 mg/kg resulted in reduction of the number of fungal cfus in the inoculated left lung. Compared with Fungizone, both AmBisome 1 mg/kg/day and AmBisome 10 mg/kg/day significantly prevented dissemination from the infected left lung to the right lung. In addition, both AmBisome regimens reduced hepatosplenic dissemination, and the 10 m/kg dosage fully prevented this complication. In conclusion, when compared with Fungizone, in this model AmBisome is more effective in reducing dissemination of unilateral, pulmonary aspergillosis, even when given in relatively low dosage. Such low dosages may have a place in prophylactic settings.

Topics: Agranulocytosis; Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Deoxycholic Acid; Disease Models, Animal; Drug Combinations; Liposomes; Lung Diseases, Fungal; Rats

The authors test antibiotic strategies aimed at either mitigating bacterial translocation from the gut or delivering antibiotics specifically concentrated by the pancreas for prevention of early secondary infection after acute necrotizing pancreatitis.. Infection currently is the principal cause of death after severe pancreatitis. The authors have shown that the risk of bacterial infection correlates directly with the degree of tissue injury in a rodent model of pancreatitis. Bacteria most likely arrive by translocation from the colon.. Severe acute necrotizing pancreatitis was induced in rats by a combination of low-dose controlled intraductal infusion of glycodeoxycholic acid superimposed on intravenous cerulein hyperstimulation. At 6 hours, animals were randomly allocated to five treatment groups: controls, selective gut decontamination (oral antibiotics and cefotaxime), oral antibiotics alone, cefotaxime alone, or imipenem. At 96 hours, surviving animals were killed for quantitative bacterial study of the cecum, pancreas, and kidney.. The 96-hour mortality (35%) was unaffected by any treatment regimen. Cecal gram-negative bacteria were significantly reduced only by the oral antibiotics. Pancreatic infection was significantly reduced by full-gut decontamination and by imipenem, but not by oral antibiotics or by cefotaxime alone. Renal infection was reduced by both intravenous antibiotics.. Early pancreatic infection after acute necrotizing pancreatitis can be reduced with a full-gut decontamination regimen or with an antibiotic concentrated by the pancreas (imipenem) but not by unconcentrated antibiotics of similar spectrum (cefotaxime) or by oral antibiotics alone. These findings suggest that 1) both direct bacterial translocation from the gut and hematogenous seeding interplay in pancreatic infection while hematogenous seeding is dominant at extrapancreatic sites and 2) imipenem may be useful in clinical pancreatitis.

Topics: Acute Disease; Administration, Oral; Amphotericin B; Animals; Bacteria; Bacterial Infections; Bacterial Physiological Phenomena; Cecal Diseases; Cefotaxime; Colistin; Disease Models, Animal; Drug Therapy, Combination; Imipenem; Injections, Intravenous; Kidney Diseases; Male; Necrosis; Pancreas; Pancreatic Diseases; Pancreatitis; Rats; Rats, Sprague-Dawley; Survival Rate; Tobramycin

The G test containing factor G, fractioned from the Limulus lysate, was used to detect (1-3)-beta-D-glucan in a rat model of aspergillosis. Aspergillus fumigatus strain MF-13, 1 x 10(4) conidia, were inoculated transtracheally into rats treated with cortisone acetate (100 mg/kg) and fed a low-protein (8%) diet. Increased serum (1-3)-beta-D-glucan was found on the sixth day after inoculation in concentrations of 370 +/- 178 pg/ml (mean +/- SD) in untreated controls, and 154 +/- 43 pg/ml in rats treated with 0.5 mg/kg of amphotericin B. On day 11 (1-3)-beta-D-glucan concentrations were 2,590 +/- 2,940 pg/ml and 448 +/- 442 pg/ml, respectively. The elevation in levels of (1-3)-beta-D-glucan increased in correlation with the elevation of galactomannan antigen titers; (1-3)-beta-D-glucan is thus measurable during experimental aspergillosis in rats.

Topics: Amphotericin B; Animals; Aspergillosis; Aspergillus fumigatus; beta-Glucans; Disease Models, Animal; Galactose; Glucans; Horseshoe Crabs; Lung; Male; Mannans; Rats; Rats, Sprague-Dawley

Pulmonary aspergillosis is a serious opportunistic disease in patients with immune suppression. Prophylactic measures would be highly beneficial because treatment often fails after infection occurs. The principle objective of this study was to evaluate the prophylactic efficacy of aerosolized liposomal (AmBisome) and non-liposomal (Fungizone) amphotericin B in a murine model. Immunocompromised mice were treated prophylactically for 3 days with AmBisome or Fungizone using a small particle aerosol generator. Intranasal challenge was with a high (10(8)), medium (10(7)), or low (10(6)) level of Aspergillus fumigatus spores. AmBisome nebulized more uniformly, resulting in very consistent chamber air concentrations. Total dose, however, was nearly the same for each formulation. Survival was prolonged in animals treated with both formulations at the 10(8) and 10(7) challenge levels. Quantitative lung cultures showed that organisms were completely cleared from the lungs in the low challenged group, with both formulations, whereas the high challenge proved overwhelming for both formulations. With the middle challenge, however, AmBisome cleared 80% of the lungs, whereas Fungizone cleared none. Lung drug retention of AmBisome treated animals was more than eight times higher than Fungizone at the time of challenge. BUN and creatinine values in animals treated with both formulations were not elevated. These results suggest that AmBisome is more effective than Fungizone when given as a prophylactic aerosol in this model.

Topics: Aerosols; Amphotericin B; Animals; Aspergillosis; Body Weight; Disease Models, Animal; Drug Delivery Systems; Female; Kidney; Lung; Lung Diseases, Fungal; Mice; Survival Rate

The kinetics of amphotericin B (AMB) concentrations in plasma and interstitial fluid were studied in an experimental model of Candida albicans infection in rabbits. Rabbits were infected by subcutaneously implanted fibrin clots containing the yeast. Three groups of five rabbits received a 4 mg kg-1 AMB infusion. AMB (Fungizone) was dissolved in 5% glucose (group I) or in 20% Intralipid at a final concentration of 1.5 (group II) or 3 mg mL-1 (group III). AMB was measured by liquid chromatography in plasma and in trypsin-dissolved fibrin clots up to 72 h after the infusion. No significant differences in AMB plasma and interstitial-fluid concentration kinetics between the three modes of administration were found. AMB penetration into fibrin clots was slow, with no significant differences between treatments. Thus, formulation of AMB in Intralipid does not modify either the drug's interstitial or plasma kinetics at equivalent doses.

Topics: Amphotericin B; Animals; Candida albicans; Candidiasis; Chromatography, High Pressure Liquid; Computer Simulation; Disease Models, Animal; Drug Delivery Systems; Fat Emulsions, Intravenous; Fibrin; Glucose; Male; Rabbits; Skin

Mice lethally infected with Candida albicans were exposed to small-particle aerosols containing amphotericin B-liposomes. The drug, when administered twice daily for 2 h (0.58 mg/kg of body weight per day) on days 1, 2, and 3 postinoculation, significantly reduced the numbers of Candida organisms in the kidneys. Aerosol treatment increased the survival time of mice given 2 2-h treatments once a week for 4 weeks. A twice-weekly, 2-h small-particle aerosol administration of amphotericin B-liposomes for 1, 2, or 3 weeks significantly increased both the mean time of survival and percent survival.

Topics: Administration, Intranasal; Aerosols; Amphotericin B; Animals; Candida albicans; Candidiasis; Colony Count, Microbial; Disease Models, Animal; Drug Carriers; Female; Kidney; Liposomes; Male; Mice; Mice, Inbred Strains; Particle Size; Spleen

The efficacy of a new triazole antifungal agent, saperconazole, in a murine model of disseminated candidiasis was studied. Mice were intravenously infected with Candida albicans blastoconidia and treated for 14 days with oral saperconazole, intraperitoneal amphotericin B, or a combination of these. Amphotericin B alone was the most efficacious in prolonging survival and in decreasing renal colony counts, usually with complete sterilization of the kidneys by the end of the treatment course. Saperconazole improved survival rates and effected a decrease in renal colony counts, but kidneys were not microbiologically sterilized. Combination therapy with saperconazole and amphotericin B did not result in a decrease in the efficacy of amphotericin B by either end point (survival or renal colony counts). High-pressure liquid chromatographic analysis of saperconazole concentrations in serum indicated low levels of absorption of the drug. We conclude that saperconazole is effective in the treatment of murine invasive candidiasis and that the theoretical concern about adverse interactions between the two drugs does not apply to the dosages studied in these experiments.

Topics: Absorption; Amphotericin B; Animals; Azoles; Candidiasis; Chromatography, High Pressure Liquid; Colony Count, Microbial; Disease Models, Animal; Drug Interactions; Drug Therapy, Combination; Kidney; Lethal Dose 50; Male; Mice; Mice, Inbred ICR

Combination antifungal therapy was assessed in an immunosuppressed rabbit model of invasive aspergillosis. Treatment with fluconazole, amphotericin B, or a combination of both significantly prolonged survival of animals lethally challenged with Aspergillus fumigatus. High-dose amphotericin B was the most effective therapy for invasive aspergillosis. Although no antagonism was seen when fluconazole was given prophylactically or therapeutically in combination with amphotericin B, combination therapy did not augment the antifungal activity of amphotericin B. Animals given a sublethal challenge of A. fumigatus had lower mortality rates when given amphotericin B, fluconazole as treatment or prophylaxis, or various combination therapies. Only animals treated with flucytosine had mortality rates comparable to those of controls. No antagonism was observed with combinations of fluconazole and amphotericin B, flucytosine and amphotericin B, or fluconazole and flucytosine. These observations provide evidence that fluconazole, flucytosine, and amphotericin B used in various combinations are not antagonistic and may provide some insight into the treatment of invasive aspergillosis in humans.

Topics: Amphotericin B; Animals; Antigens, Fungal; Aspergillosis; Disease Models, Animal; Drug Therapy, Combination; Fluconazole; Immunosuppression Therapy; Rabbits; Survival Analysis; Tissue Distribution

Systemic and gastrointestinal infection was established in infant (15-19 days old) mice after oral-intragastric challenge with Candida albicans. All survivors retained high levels of organisms in the liver, kidney, spleen, stomach and intestine up to the 24th post infection day. These animals with persistent infections were used to study the efficacy of short term antifungal therapy. Drug treatment was initiated on 13th day for a two week period, treatment with fluconazole was compared with amphotericin B, and 5 fluorocytosine. The results suggest that fluconazole is a useful drug in the treatment of gastrointestinal candidiasis.

Topics: Amphotericin B; Animals; Candidiasis; Disease Models, Animal; Fluconazole; Flucytosine; Fungemia; Gastrointestinal Diseases; Mice

In experimental visceral leishmaniasis, euthymic but not athymic (nude) BALB/c mice respond to conventional treatment with pentavalent antimony, indicating that the in vivo efficacy of antimony is T cell dependent. This finding correlates with frequent antimony treatment failures for T-cell-deficient patients with visceral leishmaniasis. To determine whether the in vivo efficacies of alternative antileishmanial agents also require T cells, Leishmania donovani-infected euthymic and nude BALB/c mice were treated with pentamidine or amphotericin B. Pentamidine induced leishmanistatic activity in euthymic mice but had little effect in nude mice. In contrast, amphotericin B exerted potent leishmanicidal activities in both euthymic and nude animals. These results suggest that amphotericin B may be of particular use for T-cell-deficient patients with visceral leishmaniasis.

Topics: Amphotericin B; Animals; Disease Models, Animal; Female; Immunocompromised Host; Immunosuppression Therapy; Leishmania donovani; Leishmaniasis, Visceral; Mice; Mice, Inbred BALB C; Mice, Nude; Pentamidine; T-Lymphocytes

Current treatment modalities for bronchopulmonary aspergillosis are not very satisfying. We determined the in vitro activity of recently available azoles against Aspergillus fumigatus, Aspergillus flavus and Aspergillus niger. Subsequently, these agents were evaluated in an animal model of bronchopulmonary aspergillosis using A. fumigatus as test organism. In vitro, detectable activity was only found for itraconazole (all minimal inhibitory concentrations, MICs, less than or equal to 3.2 micrograms/ml). The MICs for SCH39304 were greater than or equal to 12.8 micrograms/ml and greater than or equal to 25.6 micrograms/ml for ketoconazole and fluconazole. In vivo, amphotericin B was the most active agent tested, and SCH39304 was the most active azole in terms of survival and reduction in lung weight, followed by itraconazole. Ketoconazole and fluconazole did not improve survival nor reduce the lung weight of infected animals. We conclude, (1) that in vitro activity of azoles against aspergilli does not always correlate with in vivo activity; (2) that in vivo, SCH39304 was the most active azole tested, followed by itraconazole; (3) that for those agents for which data about effectiveness in human pulmonary aspergillosis are available (amphotericin B, ketoconazole, itraconazole) antifungal activity in our model corresponds to activity as seen in human beings, and (4) that SCH39304 and itraconazole are rational choices for clinical trials in human pulmonary aspergillosis.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillosis, Allergic Bronchopulmonary; Aspergillus; Aspergillus flavus; Aspergillus fumigatus; Disease Models, Animal; Itraconazole; Ketoconazole; Male; Rats; Rats, Inbred Strains; Triazoles

A comparative study, using 5 antifungal drugs for the treatment of an experimental model of murine cryptococcosis, was carried out. One hundred and eighty Balb C mice, divided in 18 groups of 10 animals each, were intraperitoneally inoculated with 10(7) cells of Cryptococcus neoformans var. neoformans. Twelve groups were treated with different schedules beginning 5 days after inoculation, for 2 or 4 weeks. The treatments were the following: amphotericin B (6 mg/kg/every other day, intraperitoneally); 5-fluorocytosine (300 mg/kg/day, by gavage); amphotericin B (6 mg/kg/every other day, intraperitoneally) in association with 5-fluorocytosine (300 mg/kg/day, by gavage); fluconazole, itraconazole and Sch 39.304 (all at the daily dose of 16 mg/kg, by gavage). The six remaining groups were used as controls and received the solvent for the drugs. The evaluation of the efficacy of the different treatments was based on: survival time; macroscopy of brain, lungs, liver and spleen at autopsies; presence of encapsulated yeasts in microscopic examination of wet preparations of these organs; and cultures of a concentrated suspension of brain and lungs. In the animals treated for 2 weeks, the combination of amphotericin B + 5-fluorocytosine was the most useful; it negativized the micro and macroscopic findings as well as 90% of the cultures, and prolonged the survival time up to 60 days. Sixty per cent of the mice which received amphotericin B exhibited the same survival time and macroscopic findings as those treated with the association of amphotericin B + 5-fluorocytosine. Among the azolic compounds, Sch 39.304 proved to be the most effective in the prolongation of survival time.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Amphotericin B; Animals; Antifungal Agents; Cryptococcosis; Cryptococcus neoformans; Disease Models, Animal; Drug Administration Schedule; Drug Therapy, Combination; Fluconazole; Flucytosine; Itraconazole; Ketoconazole; Mice; Mice, Inbred BALB C; Triazoles

Topics: Acetylmuramyl-Alanyl-Isoglutamine; Adjuvants, Immunologic; Amphotericin B; Animals; Aspergillosis; Aspergillus fumigatus; Cefmenoxime; Disease Models, Animal; Immunocompromised Host; Klebsiella Infections; Klebsiella pneumoniae; Lung Diseases, Fungal; Male; Mice; Pneumonia; Rats

We studied the in vivo antifungal activity of azoles in humans and in a murine model of disseminated trichosporonosis. Eight patients infected with Trichosporon species were treated with fluconazole, SCH 39304, or miconazole for 2-26 weeks. Four patients had fungemia, two patients had disseminated trichosporonosis, and one patient each had soft-tissue infection and cystitis. Response of trichosporonosis to azoles was seen in all eight patients, although one patient died with disseminated aspergillosis while still receiving SCH 39304. A literature review indicated that responses to ketoconazole or miconazole were noted in four patients with trichosporonosis. In the experimental infection, amphotericin B, SCH 39304, and fluconazole were effective in prolonging survival and reducing fungal counts in the kidneys of mice infected with a clinical strain of Trichosporon beigelii. Fluconazole but not amphotericin B prolonged survival of mice infected with a clinical strain of Trichosporon capitatum. We conclude that azoles represent effective therapy for infection with Trichosporon species.

Topics: Adult; Aged; Amphotericin B; Animals; Antifungal Agents; Child, Preschool; Disease Models, Animal; Female; Fluconazole; Humans; Immunocompromised Host; Male; Mice; Miconazole; Middle Aged; Mycoses; Triazoles; Trichosporon

The combination of intravenous flucytosine (FC) in 0.9% saline (NaCl) and amphotericin B (AmB) provides synergistic antifungal activity and is associated with a lower incidence of nephrotoxicity than with AmB treatment alone. This study was conducted to examine whether flucytosine can influence renal function and whether it can modify the acute and chronic renal responses to AmB in the rat. In the in situ perfused rat kidney, FC at a concentration of 10 mg/kg/min for 15 min had a vasodilator effect, increasing renal blood flow by 2.5 +/- 0.7 ml/min, an effect not observed with vehicle. After the infusion of FC was stopped for 15 min, AmB induced a decrease in renal blood flow similar to that with both FC and vehicle. In a second series of studies, AmB (5 mg/kg/day intraperitoneally) was administered to four groups of rats for 7 days. In addition, the following groups received the intravenous daily interventions indicated: group 1, 5% dextrose in water (15 ml/kg/12 h); group 2, FC (150 mg/kg/12 h) in 0.9% saline (15 ml/kg/12 h); group 3, 0.9% saline (15 ml/kg/12 h); and group 4, FC (150 mg/kg/12 h) in 5% dextrose in water. Group 1 sustained a 77% decrease in creatinine clearance over the 7 days and a threefold increase in serum creatinine concentration (P of < 0.05). Groups 2, 3, and 4 sustained significantly less nephrotoxicity, with no change in serum creatinine concentration and only 38, 41, and 53% decreases in creatinine clearance, respectively (P of < 0.05), compared with that for group 1. AmB levels in renal tissue varied inversely to creatinine clearance (r of 0.57, P of < or = 0.005). However, no significant differences were found in levels in tissue between groups (P of 0.06). The results of this study suggest that FC has a small but significant effect in reducing chronic AmB-induced nephrotoxicity. This amelioration of renal injury is independent of saline administration. There was evidence that the extent of renal uptake of AmB related to the efficiency of renal function at the end of the experiment.

Topics: Amphotericin B; Animals; Disease Models, Animal; Drug Combinations; Drug Interactions; Flucytosine; Kidney Diseases; Kidney Function Tests; Male; Rats; Rats, Sprague-Dawley; Renal Circulation

The efficacy of orally and intravenously administered saperconazole against Aspergillus fumigatus was assessed in an immunosuppressed temporarily leukopenic rabbit model of invasive aspergillosis and compared with that of amphotericin B. Oral saperconazole at dosages of 5, 10, and 15 mg/kg of body weight per day improved survival compared with that of controls. In addition, saperconazole at 10 and 15 mg/kg/day reduced the tissue burden and reduced levels of circulating antigen, which correlated with increasing dosages of saperconazole. Intravenous saperconazole produced levels in serum more than 10-fold that of oral therapy. Intravenous saperconazole not only improved survival and reduced antigen levels but also significantly eradicated A. fumigatus from tissues compared with those of controls and was as effective as amphotericin B in these studies. Saperconazole was effective in the treatment of experimental invasive aspergillosis and demonstrates the potential of the newer azoles in therapy for invasive aspergillosis.

Topics: Administration, Oral; Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Azoles; Disease Models, Animal; Injections, Intravenous; Microbial Sensitivity Tests; Rabbits

The embryotoxic action of amphotericin B and its methyl derivative was compared in rats after their intravenous and intraamniotic administration. The concentrations of amphotericin B and its methyl derivative in the amniotic cavity on days 13, 14 and 15 of pregnancy were 1.5 and 36 micrograms/ml, respectively. When administered intravenously during the preimplantation period the antibiotics had no embryotoxic action. Intravenous administration of amphotericin B in a dose of 500 micrograms/kg and its derivative in a dose of 2000 micrograms/kg during organ genesis induced a decrease in the craniocaudal size. In a dose of 3000 micrograms/kg administered intravenously the methyl derivative of amphotericin B induced an increase in postimplantation death rates. Administration of amphotericin B to the amniotic cavity had no damaging action. Administration of the methyl derivative on day 15 of pregnancy led to anomalous development of the lower extremities and slower ossification. The threshold doses by the embryotoxic action for intravenous administration are 500 micrograms/kg for amphotericin B and 2000 micrograms/kg for the methyl derivative. Administration of the antibiotics to the amniotic cavity revealed potential teratogenic properties of the amphotericin B methyl derivative.

Topics: Abnormalities, Drug-Induced; Amnion; Amphotericin B; Animals; Disease Models, Animal; Dose-Response Relationship, Drug; Female; Fetal Death; Fetal Growth Retardation; Hindlimb; Injections; Injections, Intravenous; Pregnancy; Rats; Teratogens

A rabbit model of exogenous Candida albicans endophthalmitis was used to determine if intravitreal corticosteroids combined with an efficacious antifungal agent enhanced fungal proliferation and ocular destruction, or if the combination can suppress the inflammatory and immunogenic response that causes retinal and uveal destruction. Exogenous Candida albicans endophthalmitis was experimentally induced in 20 rabbit eyes. Eight eyes received intravitreal amphotericin B alone; eight eyes received amphotericin B plus dexamethasone. Four eyes served as controls. By clinical grading on the fourth day after infection, the vitreous of the eyes in the two drug-treated groups was significantly clearer in comparison to that of eyes in the control group. By the seventh day after infection, the eyes treated with amphotericin B plus dexamethasone had significantly clearer vitreous in comparison to the eyes receiving only amphotericin B (P = 0.0017). Quantitative culture results were negative in both treatment groups, and histopathologic examination confirmed the clinical grading. Contrary to current beliefs, there was no evidence that the addition of corticosteroids impaired antifungal activity or enhanced fungal proliferation.

Topics: Amphotericin B; Animals; Candidiasis; Dexamethasone; Disease Models, Animal; Drug Therapy, Combination; Endophthalmitis; Eye Infections, Fungal; Fundus Oculi; Injections; Rabbits; Vitreous Body

Systemic fusarial infections have emerged as a significant cause of mortality in cancer patients. Yet, little is known about the management of these infections. The in vivo antifungal activity of amphotericin B in CF1 mice with disseminated fusarial infections was studied. Two pathogenic strains of Fusarium solani were used. Intraperitoneal administration of amphotericin B in daily doses of 0.5, 1, and 2 mg/kg for less than or equal to 10 days did not prolong survival of treated animals. Clearance of F. solani from kidneys was similar in mice treated with 1 mg/kg per day of amphotericin B and in untreated animals. These results are in agreement with the known in vitro and in vivo resistance of Fusarium species to amphotericin B.

Topics: Amphotericin B; Animals; Disease Models, Animal; Drug Tolerance; Fusarium; Male; Mice; Microbial Sensitivity Tests; Mycoses

The efficacy of liposomal amphotericin B bearing anticandidal antibodies (LAMB-Ab) was investigated in the treatment of systemic candidiasis in a murine model made neutropenic by an intraperitoneal injection of cyclophosphamide. Treatment with a single dose (0.6 mg amphotericin B kg-1 body weight) of LAMB-Ab resulted in an improved survival of neutropenic mice infected with Candida albicans compared to neutropenic mice treated with identical doses of liposomal amphotericin B or free amphotericin B.

Topics: Amphotericin B; Animals; Antibodies, Fungal; Candida albicans; Candidiasis; Disease Models, Animal; Liposomes; Mice; Neutropenia

Male Sprague-Dawley rats were treated with cortisone acetate and fed a low-protein diet for 3 weeks. At the end of week 2, animals were infected intratracheally with 10(5) conidia of Aspergillus fumigatus H11-20. Despite discontinuation of steroids and the low-protein diet 1 week after the infection, 94% of controls died of invasive pulmonary aspergillosis within 3 weeks postinfection. When rats were treated with a single dose of 1.6 mg of aerosolized amphotericin B per kg of body weight 48 h prior to the infection, mortality was reduced to 11% within 3 weeks postinfection. Despite apparent good health and rapid weight gain, all survivors showed multiple lesions in histopathological sections of the lungs, and 10(3) to 10(4) CFU of aspergilli was recovered from cultures of their lungs. With discontinuation of immunosuppression, the infection was slowly cleared; however, when cortisone acetate was restarted during week 5, reactivation of progressive invasive pulmonary aspergillosis was observed. On the basis of these results, we conclude that a single low dose of aerosolized amphotericin B prophylaxis is effective in preventing an exogenous aspergillus infection of the lung. Additional therapy is needed to prevent recurrent infection caused by endogenous aspergilli when immunosuppression is resumed.

Topics: Amphotericin B; Animals; Aspergillosis; Chronic Disease; Disease Models, Animal; Immune Tolerance; Lung Diseases, Fungal; Male; Rats; Rats, Inbred Strains; Recurrence; Time Factors

The ability of viable and nonviable Saccharomyces boulardii to protect gnotobiotic mice from Clostridium difficile induced mortality was tested. With the exception of irradiated S. boulardii, which retained some activity, only viable yeast protected the mice from lethality. The survival of C. difficile infected mice was dependent on the dose of the yeast provided in the drinking water.

Topics: Amphotericin B; Animals; Bacterial Proteins; Bacterial Toxins; Cecum; Clostridioides difficile; Cytotoxins; Diarrhea; Disease Models, Animal; Enterocolitis, Pseudomembranous; Germ-Free Life; Mice; Saccharomyces

Aspergillus terreus was isolated from a case of Keratomycosis. The patient, a 50 year old, female presented with a large corneal ulcer with hypopyon. The direct microscopic examination of the scrapings revealed hyaline, thin, septate and branched hyphae. In vitro some antimycotics (amphotericin B, 5-fluorocytosine, oxiconazole, amorolfine and ketoconazole) were tested against A. terreus by agar dilution method. Ketoconazole with MIC of 3 micrograms/ml after 7 days of incubation was most effective followed by oxiconazole (10 micrograms/ml). Experimental corneal ulcer was produced by injecting intralamellary 0.1 ml of the spore suspension containing 10 x 10(6) cfu/ml into the eyes of previously immunocompressed albino rabbits. Histopathologic examination showed infiltration and large destruction of the corneal stroma. Subconjunctival oxiconazole therapy exhibited complete cure. Based on our findings, a clinical evaluation of oxiconazole in human keratomycosis seems to be justified.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus; Corneal Ulcer; Disease Models, Animal; Female; Flucytosine; Humans; Imidazoles; Ketoconazole; Male; Middle Aged; Morpholines; Rabbits

Candida infection caused by intravenous or intracerebral contamination with a clinical strain of C. albicans 1755 was studied comparatively on 230 albino mice. The contamination doses ranged from 10(6) to 4 . 10(7) CFU/mouse. The developing infection could be characterized as Candida encephalomeningitis complicated by generalized candidiasis. Both the contamination routes mainly led to affections of the brain, kidneys and heart. The same distribution pattern of the pathogen was observed when the culture killed by heating was administered. The intracerebral route had advantages in chemotherapeutic studies since it induced less severe and more prolonged infection. Acute purulent inflammation of the brain and kidneys developing immediately after the contamination by days 5 to 6 was replaced by a granulomatous reaction and fibroplastic processes. Decreased acute inflammation along with changes in the nature of the pathogen vegetation and morphotinctorial properties in the affected organs can be used as a criterion of the antimycotic agent efficacy. A system for estimating pathomorphological changes in the tissues and the pathogen state is described and its use is illustrated with application of amphotericin B, mycoheptin and 5-phthorcytosine.

Topics: Amphotericin B; Animals; Antifungal Agents; Brain; Candidiasis; Colony Count, Microbial; Disease Models, Animal; Flucytosine; Injections; Injections, Intravenous; Mice; Polyenes

In a model of bronchopulmonary aspergillosis terbinafine did not improve survival of experimental animals in doses up to 80 mg/kg/day despite adequate lung concentrations. Pretreatment and aerosolization of the compound were also ineffective. Terbinafine was markedly less active in vitro when serum was used instead of Yeast-Nitrogen-Glucose-broth. It is concluded that a lack of bioavailability in the presence of serum may explain the lack of activity of terbinafine in experimental aspergillosis.

Topics: Aerosols; Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus flavus; Aspergillus fumigatus; Aspergillus niger; Biological Availability; Disease Models, Animal; Lung; Lung Diseases, Fungal; Male; Naphthalenes; Rats; Rats, Inbred Strains; Terbinafine

To investigate the potential use of fluconazole for prevention and treatment of disseminated candidiasis in granulocytopenic patients, its in vivo antifungal activity was studied in three models of disseminated candidiasis in persistently granulocytopenic rabbits: acute, subacute, and chronic disseminated candidiasis. Fluconazole was compared with the combination of amphotericin B and flucytosine for preventive, early, and late treatment of disseminated candidiasis, depending on the model. Fluconazole was most effective when used for preventive or early treatment of acute and subacute disseminated candidiasis. When compared with the combination of amphotericin B plus flucytosine, fluconazole was similarly effective in early treatment of acute and subacute disseminated candidiasis. When treatment was delayed 6 days after established infection, fluconazole was less active in clearing tissues in comparison with its activity in preventive and early treatment. The combination of amphotericin B plus flucytosine, however, was significantly more active than fluconazole in treatment of chronic disseminated candidiasis in all tissues. In summary, fluconazole was most effective against disseminated candidiasis in persistently granulocytopenic rabbits when used for prevention or early treatment.

Topics: Acute Disease; Agranulocytosis; Amphotericin B; Animals; Candidiasis; Chronic Disease; Disease Models, Animal; Female; Fluconazole; Flucytosine; Kidney; Liver; Rabbits; Specific Pathogen-Free Organisms

The triazole Bay R 3783 was compared with fluconazole, itraconazole, ketoconazole, and amphotericin B in rodent models of superficial and systemic candidiasis, meningocerebral cryptococcosis, and pulmonary aspergillosis. Overall, Bay R 3783 was comparable or slightly superior to fluconazole and markedly superior to itraconazole and ketoconazole in both survival and short-term organ load experiments in models of candidiasis and cryptococcosis but was less effective than amphotericin B. Of the antifungal agents tested, only Bay R 3783 and itraconazole showed any efficacy in the model of pulmonary aspergillosis.

Topics: Administration, Oral; Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Candidiasis; Cryptococcosis; Disease Models, Animal; Drug Administration Schedule; Evaluation Studies as Topic; Female; Fluconazole; Itraconazole; Ketoconazole; Lung Diseases, Fungal; Male; Meningitis; Mice; Pharmaceutical Vehicles; Rats; Rats, Inbred Strains; Triazoles

To investigate the potential use of SCH-39304 for the prevention and treatment of disseminated candidiasis in granulocytopenic patients, we studied its in vivo antifungal activity as preventive, early, and late treatments in three models (acute, subacute, and chronic) of disseminated candidiasis in persistently granulocytopenic rabbits. SCH-39304 was an effective as amphotericin B alone and fluconazole alone for the prevention of disseminated candidiasis. SCH-39304 alone and fluconazole alone were as effective as amphotericin B plus flucytosine for early treatment of subacute disseminated candidiasis. When treatment was delayed for 5 days to establish chronic disseminated candidiasis, SCH-39304 was less effective than amphotericin B plus flucytosine. In comparison with different treatment regimens, SCH-39304 was more effective in early and preventive treatment. Thus, SCH-39304 was comparable to treatment control regimens in prevention and early treatment of subacute disseminated candidiasis. SCH-39304 also was most effective in granulocytopenic rabbits with disseminated candidiasis when used for prevention or early treatment.

Topics: Agranulocytosis; Amphotericin B; Animals; Anti-Bacterial Agents; Antifungal Agents; Candida albicans; Candidiasis; Disease Models, Animal; Female; Fluconazole; Immunosuppression Therapy; Rabbits; Triazoles

The effect of cholesterol in neutral, positively and negatively charged liposomes on the toxicity, therapeutic efficacy, and alteration in the tissue distribution pattern of amphotericin B (Amp-B) in normal and infected mice was studied. It was observed that inclusion of cholesterol (CHOL) into egg phosphatidylcholine (EPC) liposomes increased the LD50 of Amp-B from 5.3 to 8.5 mg/kg body weight. In the case of phosphatidylserine (PS) liposomes as well as stearylamine (SA) liposomes, cholesterol incorporation had no effect in altering the toxicity of the drug. The survival pattern of animals with all types of liposomal formulation of Amp-B was similar. The tissue distribution studies indicated that in the case of normal mice, cholesterol inclusion in all types of liposomes increased the organ concentration of the drug in various tissues. In infected animals, the concentration of Amp-B in all organs was increased when cholesterol was included in EPC and EPC/PS liposomes. The organ concentration of Amp-B in lung and liver after 1 h of injection was the same in the case of EPC/SA and EPC/SA/CHOL liposomes. Considering the observations on toxicity, therapeutic efficacy, and tissue distribution, it was suggested that cholesterol had a beneficial therapeutic effect on neutral EPC liposomes.

Topics: Amphotericin B; Animals; Aspergillosis; Cholesterol; Colony-Forming Units Assay; Disease Models, Animal; Drug Carriers; Lethal Dose 50; Liposomes; Male; Mice; Mice, Inbred BALB C; Tissue Distribution

A murine model of focal hepatic candidiasis which we suggest simulates certain conditions of this clinical variant of systemic candidiasis in leukemic patients is described. We have shown that outbred mice inoculated with Candida albicans by the oral-intragastric route as infants (6 days old) and then immunocompromised by cyclophosphamide and cortisone acetate treatment 2 weeks later demonstrate systemic spread of the opportunistic pathogen to the liver, lungs, spleen, and kidneys. Treatment with the immunosuppressive drugs cyclophosphamide and cortisone acetate resulted in alteration of the normal integrity of the mucosal epithelium of the gut as well as in granulocytopenia. Approximately 55% of the animals with C. albicans infections in the liver demonstrated hepatic abscesses. After these same infected, immunocompromised animals were treated with suboptimal dosages of antifungal agents (cilofungin or amphotericin B), either by intraperitoneal or subcutaneous (s.c.) routes, persistent hepatic abscesses were fewer in number and delimited by a distinct outer layer of host tissue but still contained large numbers of the viable pathogen. Blood cell counts indicated that these antifungal drug-treated animals had reestablished approximately the same number of leukocytes per microliter of blood as estimated prior to the immunocompromising drug treatment. Similar conditions in leukemic patients who were in remission and who were undergoing antifungal drug therapy for systemic candidiasis have been reported. Clearance of hepatic infections in mice was accomplished by using appropriate concentrations of amphotericin B administered by daily intraperitoneal or s.c. injection for 5 to 7 days or cilofungin by continuous s.c. infusion for 7 days. However, systemic antifungal therapy did not significantly reduce numbers of C. albicans cells in the stomach and esophagus. Persistent foci of gastrointestinal colonization by C. albicans, especially in the region of the cardial-atrium fold of the stomach of these mice, are reservoirs of the opportunistic pathogen from which reinfection may occur, leading to relapse of systemic candidiasis.

Topics: Agranulocytosis; Amphotericin B; Animals; Body Weight; Candidiasis; Cortisone; Cyclophosphamide; Disease Models, Animal; Drug Therapy, Combination; Echinocandins; Esophagitis, Peptic; Immune Tolerance; Incidence; Injections, Intravenous; Injections, Subcutaneous; Liver Diseases; Mice; Microbial Sensitivity Tests; Organ Specificity; Peptides; Peptides, Cyclic

Pneumocystis carinii pneumonia is often the terminal event for patients with the acquired immunodeficiency syndrome. Eflornithine (DL-alpha-difluoromethylornithine [DFMO]; Ornidyl; Merrell Dow Research Institute, Cincinnati, Ohio) has been used successfully against this protozoan disease in limited clinical trials, although not all patients respond to therapy. In contrast, results of the only reported experiments with DFMO in an animal model were negative. We retested DFMO against P. carinii in an immunosuppressed rat model by inclusion of 3% DFMO in the drinking water, a dose rate about twice that used previously. A combination of trimethoprim and sulfamethoxazole, a proven anti-P. carinii agent, was used as a positive control. After 3 weeks of anti-P. carinii pneumonia therapy, the surviving rats were sacrificed and the degree of parasitosis was judged by examination of lung sections stained with silver methenamine to reveal cysts. In three separate experiments, DFMO showed definite anti-P. carinii pneumonia activity; the parasitosis of DFMO-treated animals was significantly less than that of control animals (P less than 0.001 for all experiments). DFMO was not as active as trimethoprim-sulfamethoxazole, however. Several other experimental therapies were tested, including dapsone and two additional antiprotozoal agents: suramin and diminazene aceturate (Berenil; Farbwerke Hoechst, Frankfurt, Federal Republic of Germany). Diminazene aceturate, a veterinary drug related to the standard anti-P. carinii pneumonia agent pentamidine, was very active (P less than 10(-10]. Suramin and dapsone were weakly active. The combinations suramin-diminazene aceturate and suramin-DFMO were tested, but they were antagonistic rather than synergistic.

Topics: Amphotericin B; Animals; Antiprotozoal Agents; Dapsone; Diminazene; Disease Models, Animal; Drug Combinations; Eflornithine; Female; Immunosuppression Therapy; Pneumonia, Pneumocystis; Random Allocation; Rats; Rats, Inbred Strains; Sulfamethoxazole; Suramin; Trimethoprim; Trimethoprim, Sulfamethoxazole Drug Combination

Topics: Administration, Oral; Amphotericin B; Animals; Candidiasis; Disease Models, Animal; Drug Administration Schedule; Male; Mice; Mice, Inbred ICR

Invasive pulmonary aspergillosis is a major life-threatening complication among transplant recipients and patients receiving cancer chemotherapy. In a rat model of progressive pulmonary aspergillosis that is characterized by hyphal bronchopneumonia, aerosol amphotericin B (aero-AmB; 1.6 mg/kg given 2 days before infection) significantly delayed mortality in rats compared with animals in a control group. The first death in the aero-AmB-treated group occurred on day 11, by which time seven of the eight control animals had died. The same dose of aero-AmB given as treatment (1.6 mg/kg given 24 h after infection and then daily for 6 days) was also effective. In this trial, eight of the ten animals treated with aero-AmB survived for 7 days, whereas only one of ten control animals survived. Colony counts in lung homogenates obtained 24 h after infection showed an 80-fold reduction in the number of viable spores in animals that had received 6.4-mg/kg doses of aero-AmB 2 days prior to infection. At 48 h after administering a single 1.6- or 3.2-mg/kg dose of aero-AmB, mean lung concentrations were 2.79 and 5.22 micrograms/g of tissue, respectively. We conclude, therefore, that aero-AmB kills inhaled spores and delays the progression of pulmonary aspergillosis by inhibiting mycelial proliferation.

Topics: Aerosols; Amphotericin B; Animals; Aspergillosis; Disease Models, Animal; Drug Evaluation, Preclinical; Injections, Intraperitoneal; Lung; Lung Diseases, Fungal; Male; Organ Size; Rats; Rats, Inbred Strains

The susceptibility of Candida albicans to topical amphotericin B and natamycin was evaluated in a model of stromal keratitis in Dutch-belted rabbits and compared with minimal inhibitory concentrations in vitro. Treatment was delayed 24 hr to allow invasive disease to occur and was then continued for 5 days. Ten strains of Candida albicans comprised the test panel. For amphotericin B, the minimal inhibitory concentration (MIC) by tube dilution classified the same strains as resistant or susceptible as did the in vivo response. A dose-response was observed with different concentrations of the drug. For natamycin, the MIC misclassified two strains. The rate of administration of natamycin required in this model was much higher than for amphotericin B, a therapeutic effect being observed with natamycin only when the drug was administered every 30 min during the in vivo efficacy and in vitro susceptibility with these strains is in agreement with that observed in the authors' previous studies using a model of immediate treatment.

Topics: Administration, Topical; Amphotericin B; Animals; Candida albicans; Candidiasis; Disease Models, Animal; Dose-Response Relationship, Drug; Keratitis; Microbial Sensitivity Tests; Natamycin; Rabbits

Growth of the yeast form of Sporothrix schenckii (ATCC 14804) was determined in diffusion chambers with 0.45 and 3.0 micron pore size over a period of 24 to 192 h after subcutaneous implantation into mice. Numbers of S. schenckii in 0.45 micron chambers increased significantly by 192 h when inocula of 10(3) and 10(5) colony forming units were implanted. In chambers with a pore size of 3.0 microns, only a slight decrease of fungal growth occurred, although host cells readily passed the filter membrane and phagocytosed yeast-form cells. The activities of amphotericin B, ketoconazole, itraconazole, ICI 153.066, vibunazole and potassium iodide against S. schenckii in implanted chambers were determined in terms of their effects on S. schenckii. ICI 153.066, ketoconazole, itraconazole and amphotericin B significantly reduced the numbers of reisolated S. schenckii in both types of chambers. There was a slight activity with vibunazole but none with potassium iodide.

Topics: Amphotericin B; Animals; Antifungal Agents; Disease Models, Animal; Female; Itraconazole; Ketoconazole; Mice; Potassium Iodide; Sporothrix; Sporotrichosis; Triazoles

We have recently reported the in vivo augmentation of resistance to experimental Candida albicans injection by amphotericin B in mice and have shown that this event is concurrent with the appearance in the spleen of a highly candidacidal cell population reactive in vitro against 51Cr-labeled yeast cells. In the present study we characterize these in vitro fungicidal effectors as macrophages and describe the conditions of amphotericin B treatment most suitable for inducing candidacidal activity. We also report that macrophages from intact mice can be activated in vitro to become cytotoxic against Candida. The possible mechanisms through which the amphotericin B activated macrophages exert their increased anti-Candida activity are also investigated.

Topics: Adjuvants, Immunologic; Amphotericin B; Animals; Candidiasis; Complement System Proteins; Cytotoxicity, Immunologic; Disease Models, Animal; Immune Sera; Macrophage Activation; Macrophages; Mice; Mice, Inbred Strains; Phagocytosis; Spleen

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Disease Models, Animal; Female; Flucytosine; Itraconazole; Ketoconazole; Kidney Diseases; Mice; Mice, Inbred Strains; Miconazole; Triazoles

Existing models of Candida albicans infection are semi-quantitative and do not allow continuous observations to be made on individual animals. We have used the inflammatory response in the footpad as an indirect measure of the number of yeast cells in a localised lesion. C. albicans infection of the footpad has been used in series of experiments in which changes in yeast-cell numbers in the local lesion have been compared with the degree of footpad oedema. Studies in animals treated with cyclophosphamide or amphotericin have confirmed that paw oedema parallels yeast-cell numbers in the local lesion. This quantitative approach will be helpful in the study of localised infection with C. albicans and other fungi and in the evaluation of antifungal agents.

Topics: Amphotericin B; Animals; Candida albicans; Candidiasis; Cyclophosphamide; Disease Models, Animal; Edema; Female; Foot; Inflammation; Male; Rats; Rats, Inbred Strains

Recent classifications of the several pathophysiologic types of distal renal tubular acidosis (secretory, voltage dependent, and gradient) have been based on the response of acidification parameters to a series of provocative maneuvers in vivo and in vitro. A reduction in the difference in urine and blood CO2 tension during bicarbonate loading (U-B pCO2 gradient), a widely applied parameter, has been employed as an index of reduced distal nephron proton secretion. This study was designed to test the validity of the U-B pCO2 gradient in a variety of experimental models of distal renal tubular acidosis by measuring and comparing disequilibrium pH (a direct technique to detect H+ secretion in situ) with the pCO2 in the papillary collecting duct of the rat in vivo during bicarbonate loading. Chronic amiloride, lithium chloride, and amphotericin-B administration, and the post-obstructed kidney models were employed. Amiloride resulted in an acidification defect which did not respond to sulfate infusion (urine pH = 6.15 +/- 0.08), and was associated with an obliteration of the acid disequilibrium pH (-0.26 +/- 0.05- -0.08 +/- 0.03) and reduction in papillary pCO2 (116.9 +/- 3.2 - 66.9 +/- 2.5 mmHg). The defect induced by lithium administration responded to Na2SO4 (urine pH = 5.21 +/- 0.06) but was similar to amiloride with respect to the observed reduction in disequilibrium pH (-0.04 +/- 0.02) and pCO2 (90.3 +/- 3.0 mmHg). The post-obstructed kidney model was characterized by an abnormally alkaline urine pH unresponsive to sulfate (6.59 +/- 0.06) and a reduction in disequilibrium pH (+0.02 +/- 0.06) and pCO2 (77.6 +/- 3.6 mmHg). Amphotericin-B resulted in a gradient defect as characterized by excretion of an acid urine after infusion of sodium sulfate (5.13 +/- 0.06). Unlike other models, however, amphotericin-B was associated with a significant acid disequilibrium pH (-0.11 +/- 0.05) and an appropriately elevated urine pCO2 (119.8 +/- 6.4 mmHg) which did not differ from the respective values in control rats. Thus, these findings support the use of the U-B pCO2 as a reliable means of demonstrating impaired distal nephron proton secretion in secretory and voltage-dependent forms of distal renal tubular acidosis (RTA) and supports the view that proton secretion is not impaired in gradient forms of distal RTA.

Topics: Absorption; Acid-Base Equilibrium; Acidosis, Renal Tubular; Amphotericin B; Animals; Bicarbonates; Carbon Dioxide; Disease Models, Animal; Hydrogen-Ion Concentration; Male; Nephrons; Rats; Rats, Inbred Strains

The potential of ketoconazole prophylaxis to antagonize the activity of amphotericin B against aspergilli was investigated in vitro and in neutropenic mice. Exposure of Aspergillus fumigatus (six strains) and of Aspergillus flavus or Aspergillus niger to ketoconazole resulted in a uniform increase of the minimal fungicidal activity of amphotericin B, from 0.15-0.63 mg/liter to greater than 2.5 mg/liter in a microwell assay. To test the relevance of this antagonism in vivo, we challenged neutropenic mice iv with a lethal dose of conidia from two strains of A. fumigatus and then treated the mice first with ketoconazole and then with amphotericin B or amphotericin B plus ketoconazole. Pretreatment with ketoconazole for 48 hr completely abolished the protective effect of a subsequent therapy with amphotericin B, whether ketoconazole therapy was stopped (P less than .001) or not (P less than .001). Ketoconazole given alone had no significant effect on survival. Our data show that ketoconazole not only antagonized the fungicidal activity of amphotericin B in vitro but also abolished in vivo the protective effect of the only drug shown to be useful in the therapy of aspergillosis. The clinical importance of this antagonism, which is not limited to Aspergilli in vitro, requires careful consideration before ketoconazole prophylaxis can be recommended for patients at high risk of developing invasive opportunistic fungal infections.

Topics: Amphotericin B; Animals; Aspergillosis; Disease Models, Animal; Female; Humans; In Vitro Techniques; Ketoconazole; Liver Diseases; Mice; Neutropenia; Premedication

A description is given of two methods for investigating the action of drugs against a viscerotropic Leishmania in mice. The parasite employed was isolated from a patient with kala-azar in Ethiopia. It is designated 'L. infantum LV9' and produces a visceral infection in NMRI mice. The biochemical typing characters of the parasite are described. In Method A, infected animals were treated from the 5th or 6th day after infection (D + 5 or D + 6) for five consecutive days. They were sacrificed 24 hours after the completion of drug treatment and an estimate was made of the amastigote load in the liver. A comparison of this with untreated controls gives an index of activity of a test drug, from 0 to 3. Method B is similar except that the ED50 and ED90 are determined by graphic analysis of data from graded drug doses. A comparison is made with sodium stibogluconate used as a positive drug control to yield a 'Pentostam Index'. The course of infection in BALB/c and NMRI mice is compared with that in random-bred Swiss mice in which 'L. infantum LV9' produces an inconsistent infection. An inoculum of 10(7) amastigotes produces a peak parasite intensity between D + 15 and D + 20. The ED50 and ED90 of sodium stibogluconate (Pentostam) (as Sbv) in Method B are 22 x 5 and 46 x 5 mg/kg sc daily x 5. (By Method A the single dose figures are 65 and 280 mg/kg.) For routine use a standard dose level of 120 mg/kg sc daily x 5 of Pentostam (Sbv) is used in Method B. The ED50 and ED90 of meglumine antimoniate (Glucantime) (as Sbv) in Method B are 11 x 6 and 66 x 7 mg/kg sc daily x 5. Data are given for other antimonials in Method A. Pentamidine and diminazene aceturate proved to have a slow action which was more readily demonstrated if the observation period was prolonged. Amphotericin B was moderately active but toxic to the host. The relevance of these models and a comparison of data found in the mouse and hamster are debated.

Topics: Amphotericin B; Animals; Antimony Sodium Gluconate; Disease Models, Animal; Drug Evaluation, Preclinical; Leishmania; Leishmaniasis, Visceral; Liver; Mice

Topics: Amphotericin B; Animals; Antifungal Agents; Candidiasis; Disease Models, Animal; Drug Therapy, Combination; Endophthalmitis; Fluorescein Angiography; Imidazoles; Injections, Intravenous; Ketoconazole; Miconazole; Microbial Sensitivity Tests; Piperazines; Rabbits; Retinitis; Time Factors

This study was undertaken to examine the value of mannitol as protection against the acute nephrotoxicity of amphotericin B under controlled conditions in a reproducible model of toxicity in the dog. Eleven dogs received amphotericin B, 2.5 mg x kg-1 b. wt. by i.v. infusion over a 4-h period. Six dogs were treated with mannitol, 6.25 g, i.v. every hour and five served as controls. Urinary volume (V), inulin clearance (CIn), p-aminohippurate clearance (CPAH), and Na excretion (UNaV) were measured every hour throughout the experiment. Although a higher urinary output was maintained in mannitol-treated dogs, a progressive decline in renal function was observed in treated and in control dogs. During the 4th h, mannitol-treated dogs showed higher CIn (37.4 vs. 19.7 ml x min-1 and CPAH (95 vs. 54 ml x min-1 than controls. However, statistically the differences were barely significant. The results fail to show that mannitol offers a definite protection against amphotericin B nephrotoxicity.

Topics: Amphotericin B; Animals; Disease Models, Animal; Dogs; Female; Infusions, Parenteral; Kidney Diseases; Kidney Function Tests; Mannitol

Minocycline has an additive anticryptococcal effect when combined with amphotericin B in vitro, and the combination lowers tissue counts of fungi. However, minocycline offers no survival benefit to amphotericin B therapy in murine cryptococcosis.

Topics: Amphotericin B; Animals; Cryptococcosis; Cryptococcus neoformans; Disease Models, Animal; Drug Therapy, Combination; Female; Male; Mice; Minocycline; Tetracyclines

An experimental dermatitis was established for the guinea pig and Swiss white mouse by topical application of cultures of Pityrosporum ovale, isolated from pityriasis capitis and from P. arbiculare isolated from pityriasis versicolor. Histology showed the development of the yeasts in the stratum corneum, with hyperkeratosis at the follicular ostium and in the pilous bulb: the clinical and histological appearances resembled human seborrheic dermatitis. The nude (nu/nu) mouse, the hair-less mouse and the nude rat were not susceptible to this experimental infection, probably because of the dystrophy of their pilous follicles and sebaceous glands. The experimental model permitted evaluation of antifungal agents. The Pityrosporum dermatitis disappeared rapidly after topical application of econazole or amphotericin B. No pathological differences were observed between the strains tested.

Topics: Administration, Topical; Amphotericin B; Animals; Dermatomycoses; Disease Models, Animal; Econazole; Female; Guinea Pigs; Malassezia; Male; Mice; Mice, Nude; Rats; Skin; Species Specificity

Topics: Aminoquinolines; Amphotericin B; Animals; Antimony Sodium Gluconate; Disease Models, Animal; Female; Leishmaniasis; Metronidazole; Mice; Mice, Inbred BALB C; Senegal; Wound Healing

Amphotericin B methyl ester, a water-soluble derivative of amphotericin B, is an experimental antifungal agent. Intravitreous injection of 5 and 10 micrograms of amphotericin B methyl ester in the normal rabbit eye does not cause toxic changes that can be detected clinically, microscopically, or by electroretinography. A single intravitreous injection of 5 micrograms was effective in reversing the course of exogenous Candida fungal endophthalmitis when administered within five days after inoculation of the infecting organism.

Topics: Amphotericin B; Animals; Candidiasis; Disease Models, Animal; Endophthalmitis; Injections; Mycoses; Rabbits; Vitreous Body

Amphotericin B (2.5 mg/kg, administered intravenously) increased vascular resistance (renal more than pulmonary more than systemic) and decreased glomerular filtration and urine flow 94% in 16 anesthetized female mongrel dogs. Dopamine decreased renal vascular resistance 31% in 14 dogs; when amphotericin B was given with dopamine, there was partial antagonism of amphotericin B-induced renal vasoconstriction. Saralasin partially antagonized amphotericin B-induced renal vasoconstriction in seven dogs. When amphotericin B was given during combined infusion of dopamine and saralasin in eight dogs, renal blood flow remained at initial control levels, urine flow increased above initial levels, and glomerular filtration decreased only 21% from initial values. Amphotericin B increased renal vascular resistance 296% when given alone but only 41% in dogs during injection of both dopamine and saralasin (P = 0.002). The antagonism of amphotericin B-induced renal effects by the combination of dopamine and saralasin was significant and specific for the renal vascular bed.

Topics: Amphotericin B; Angiotensin II; Animals; Anuria; Disease Models, Animal; Dogs; Dopamine; Female; Glomerular Filtration Rate; Kidney; Lung; Oliguria; Saralasin; Vascular Resistance

Prednisolone potentiated candidiasis in mice when given as dosages of 1 mg, s.c. at-1 and + 24 h in relation to the time of inoculation, i.p. with any of 4 isolates of C. albicans which differed in degree of pathogenicity. Enhancement was shown by increased intra-abdominal colonisation, haematogenous dissemination and percentage mortality. There was at least a seven-fold increase in the mean area occupied by fungal colonies in median, longitudinal sections of kidneys after prednisolone treatment. Compared with those of fungal controls, renal lesions were deficient in inflammatory cells, only a few polymorphonuclear leukocytes occurring peripherally. Amphotericin B (AmB) at a non-toxic, total dosage of 0.5 mg given in two injections of 0.25 mg, i.p. at intervals of 24 h rendered infections non-lethal, or significantly reduced their severity, when started 24 or 48 h after inoculation. When antifungal treatment was delayed until 72 h, however, early deaths occurred despite the fact that the mean renal section area occupied by pseudomycelium was little more than that of controls and fibrosis of lesions was characteristic. Early mortalities increased even further when AmB, commencing at 72 h, was combined with prednisolone. This effect was thought to be due to the release of some toxic factor(s) following the leaching of cells by AmB combined with depleted antibody levels. Ascitic fluids from infected mice given Ehrlich ascites tumour cells showed marked increases in the concentrations of alpha2 and gamma globulins. Concentrations were almost reduced to normal levels in animals treated with prednisolone and/or AmB.

Topics: Amphotericin B; Animals; Candida albicans; Candidiasis; Disease Models, Animal; Mice; Prednisolone; Species Specificity

The principal ultrastructural changes in cells of Candida albicans treated with amphotericin B (AmB), either in vitro or in vivo, and in the presence or absence of prednisolone included plasmolysis, vacuolation and destruction of organelles. Lamination of the cell wall, although discernible after 4 h antibiotic treatment in vitro, was conspicuous in vivo, especially in prednisolone-treated mice given AmB 72 h after inoculation and was seen in both phagocytosed cells and those free in inflammatory exudates. Somatic extracts from control cells and somatic extracts and leachates from AmB-treated cells showed the presence of low-grade toxic components when given i.p. to mice receiving antinomycin D(AMD) s.c. Culture filtrates were negative. Eighteen hour cultures were more toxic than those grown for 3 days and no toxicity was shown for cultures after 8 or 14 days. The behaviour of toxic materials during electrophoresis in polyacrylamide gels suggested that they were proteins of relatively high molecular weight.

Topics: Amphotericin B; Animals; Candida albicans; Candidiasis; Cell Wall; Disease Models, Animal; Mice; Mycotoxins; Organoids; Prednisolone

Endocarditis caused by Candida albicans was induced in rabbits after insertion of a catheter across the aortic valve. The mean survival time of 34 rabbits was 26 days. Only 7% of temperature recordings taken were elevated. Candida was recovered from only 9% of blood cultures taken. Precipitating and agglutinating serum antibody was detected after 12 days of infection. Antibody titers rose progressively until death in rabbits with endocarditis, whereas titers peaked early and subsequently decreased in animals that received an intravenous injection of C. albicans without precatheterization. Three groups of rabbits were treated for 6 days with amphotericin B, 5-fluorocytosine, or the two durgs in combination. Amphotericin B alone reduced the mean titer of organisms from log10 8.79 +/- 1.46 to log 10 3.1 +/- 1.9 colony-forming units/g. 5-Fluorocytosine was less effective (mean titer after 6 days of therapy was log10 7.4 +/- 0.33 colony-forming units/g). The addition of 5-fluorocytosine to amphotericin B did not increase the rate at which Candida cells were eradicated from the vegetations. These in vivo results corrleated with the failure to demonstrate an increased rate of fungicidal activity in vitro with the two drugs.

Topics: Agglutinins; Amphotericin B; Animals; Antibodies, Fungal; Aortic Valve; Candida albicans; Candidiasis; Cytosine; Disease Models, Animal; Endocarditis; Flucytosine; Kidney; Rabbits

Trichothecin (T-cin), amphotericin B (AB), and 5-fluorocytosine (FC) were compared singly and in combination for capacities to inhibit growth of Cryptococcus neoformans in culture and to protect mice bearing infections with this yeast. The minimum inhibitory concentrations for T-cin, AB, and FC were found to be 0.5, 0.2, and 5.0 mug/ml, respectively. In vitro viability studies demonstrated a marked reduction in colony counts with the AB-FC combination and additive effects with the AB-T-cin and FC-T-cin combinations for a 3-day period. In mice infected intravenously with C. neoformans, the mean effective dose for AB was 0.38 mg/kg, and for FC it was 100 mg/kg for a 30-day treatment period. No mean effective dose could be ascertained when T-cin was tested at doses of 0.1 to 50 mg/kg. Despite this, marked beneficial effects were noted in vivo with the AB-T-cin combination, whereas additive effects and indifference were observed for AB-FC and FC-T-cin combinations, respectively. High-dose T-cin controls survived despite having received a cumulative dosage of more than twice the reported (LD(50)) mean lethal dose value.

Topics: Amphotericin B; Animals; Cryptococcosis; Cryptococcus; Cryptococcus neoformans; Cytosine; Disease Models, Animal; Drug Evaluation, Preclinical; Drug Synergism; Drug Therapy, Combination; Female; Flucytosine; Male; Mice; Sesquiterpenes; Trichothecenes

The methyl ester of amphotericin B was compared with the parent compound, amphotericin B, in terms of therapeutic efficacy in experimental murine coccidioidomycosis and of toxicity. Infections were established by intraperitoneal or intratracheal inoculation with arthrospores. The mice were given either intraperitoneal or intravenous injections of drug for 30 days, according to several dosage schedules. At low doses, amphotericin B methyl ester was less effective therapeutically than was amphotericin B; however, at higher doses, amphotericin B was directly lethal and/or nephrotoxic, whereas the methyl ester was therapeutically effective and nontoxic. In contrast to amphotericin B, the methyl ester did not cause either azotemia or histopathologic changes in the kidneys.

Topics: Amphotericin B; Animals; Coccidioidomycosis; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Evaluation, Preclinical; Mice

Amphotericin B, the principal drug used for treating systemic mycoses, possesses undesirable toxic properties. The ability of this antibiotic to potentiate antifungal activity of other compounds suggests that lower doses of amphotericin B could be used in combination with a second drug without loss of therapeutic efficacy. In vitro tests demonstrated that amphotericin B potentiated rifampin against the mycelial growth phase of Coccidioides immitis but not against the spherule-endospore phase. Therapy for murine coccidioidomycosis with a combined amphotericin B-rifampin regimen was not better than treatment with amphotericin B alone; in fact, combined drugs may have been even less effective. This would have clinical significance for therapy of concurrent infections.

Topics: Amphotericin B; Animals; Coccidioides; Coccidioidomycosis; Disease Models, Animal; Drug Synergism; Drug Therapy, Combination; Male; Mice; Rifampin

The in vitro and in vivo activities of amphotericin B and 5-fluorocytosine (5-FC) alone and in combination were studied to determine possible drug interactions against two strains of Cryptococcus neoformans, one sensitive to 5-FC and one resistant to 5-FC. In vitro tube dilution studies demonstrated only additive effects with the 5-FC-sensitive organism but antagonism with eth 5-FC-resistant organism. A mouse model of cryptococcal meningitis allowed comparative drug trails in a new model for the detection of drug interactions. Drug combinations were no more effective against meningitis caused by the 5-FC-sensitive organism than the additive effects of the individual drugs. However, meningitis caused by the 5-FC-resistant Cryptococcus responded less to drug combinations than to either drug alone. Serum levels of amphotericin B and 5-FC were comparable in all groups. No evidence of toxicity from the drug combinations was found. No inhibition of development of resistance to 5-FC by the combination with amphotericin B was detected.

Topics: Amphotericin B; Animals; Cryptococcosis; Cryptococcus; Cryptococcus neoformans; Cytosine; Disease Models, Animal; Drug Interactions; Drug Resistance, Microbial; Drug Therapy, Combination; Flucytosine; Meningitis; Mice

Treatment of a transplantable leukemia in AKR mice with both amphotericin B and 1,3-Bis(2-chloroethyl)-1-nitrosourea cured a significant percentage of animals with advanced disease. Some long-term survivors developed paralysis, and they invariably demonstrated central nervous system (CNS) leukemia. Some of these animals had a systemic relapse of their leukemia, and the CNS appeared to act as a focus for systemic dissemination. The occurrence patterns and histopathologic features of the CNS leukemia in the long-term survivors were strikingly similar to those observed in humans with acute lymphoblastic leukemia.

Topics: Amphotericin B; Animals; Brain; Carmustine; Central Nervous System Diseases; Disease Models, Animal; Female; Leukemia, Experimental; Leukemia, Lymphoid; Meninges; Mice; Mice, Inbred AKR; Neoplasm Metastasis; Neoplasm Recurrence, Local; Paralysis; Spinal Cord

Topics: Abscess; Amphotericin B; Animals; Candida albicans; Candidiasis; Disease Models, Animal; Eye Diseases; Injections; Rabbits; Time Factors; Vitreous Body

Topics: Amebiasis; Amoeba; Amphotericin B; Anti-Bacterial Agents; Cerebrospinal Fluid; Disease Models, Animal; Humans; Meningoencephalitis; Respiratory Tract Infections; Sports Medicine; Staining and Labeling; Swimming; United States

Topics: Acidosis, Renal Tubular; Ammonium Chloride; Amphotericin B; Animals; Bicarbonates; Bile Acids and Salts; Body Weight; Carbon Dioxide; Creatinine; Disease Models, Animal; Hydrogen-Ion Concentration; Injections, Intraperitoneal; Kidney Concentrating Ability; Kidney Diseases; Kidney Function Tests; Male; Polyuria; Potassium; Quaternary Ammonium Compounds; Rats; Sodium

Topics: Amphotericin B; Analysis of Variance; Animals; Antibodies, Fungal; Autopsy; Blastomyces; Blastomycosis; Body Weight; Complement Fixation Tests; Disease Models, Animal; Dogs; Histoplasma; Histoplasmosis; Lung; Male; Placebos; Skin Tests

Topics: Amphotericin B; Animals; Cell Membrane; Disease Models, Animal; Endoplasmic Reticulum; Hydrogen-Ion Concentration; Mitochondria; Mucous Membrane; Perfusion; Staining and Labeling; Turtles; Urinary Bladder