cilastatin--imipenem-drug-combination and Disease-Models--Animal

We demonstrated therapeutic nonequivalence of "bioequivalent" generics for meropenem, but there is no data with generics of other carbapenems.. One generic product of imipenem-cilastatin was compared with the innovator in terms of in vitro susceptibility testing, pharmaceutical equivalence, pharmacokinetic (PK) and pharmacodynamic (PD) equivalence in the neutropenic mouse thigh, lung and brain infection models. Both pharmaceutical forms were then subjected to analytical chemistry assays (LC/MS).. The generic product had 30% lower concentration of cilastatin compared with the innovator of imipenem-cilastatin. Regarding the active pharmaceutical ingredient (imipenem), we found no differences in MIC, MBC, concentration or potency or AUC, confirming equivalence in terms of in vitro activity. However, the generic failed therapeutic equivalence in all three animal models. Its Emax against S. aureus in the thigh model was consistently lower, killing from 0.1 to 7.3 million less microorganisms per gram in 24 hours than the innovator (P = 0.003). Against K. pneumoniae in the lung model, the generic exhibited a conspicuous Eagle effect fitting a Gaussian equation instead of the expected sigmoid curve of the Hill model. In the brain infection model with P. aeruginosa, the generic failed when bacterial growth was >4 log10 CFU/g in 24 hours, but not if it was less than 2.5 log10 CFU/g. These large differences in the PD profile cannot be explained by the lower concentration of cilastatin, and rather suggested a failure attributable to the imipenem constituent of the generic product. Analytical chemistry assays confirmed that, besides having 30% less cilastatin, the generic imipenem was more acidic, less stable, and exhibited four different degradation masses that were absent in the innovator.

Topics: Animals; Bacteria; Bacterial Infections; Cilastatin; Cilastatin, Imipenem Drug Combination; Disease Models, Animal; Drug Stability; Drugs, Generic; Humans; Imipenem; Klebsiella pneumoniae; Mice; Microbial Sensitivity Tests; Pseudomonas aeruginosa; Staphylococcus aureus; Therapeutic Equivalency

Sepsis still constitutes an unmet clinical need, which could benefit from novel adjunctive strategies to conventional antibiotic therapy. The soluble form of the scavenger-like human CD6 lymphocyte receptor (shCD6) binds to key pathogenic components from Gram-positive and -negative bacteria and shows time- and dose-dependent efficacy in mouse models of monobacterial sepsis. The objective of the present work was to demonstrate the effectiveness of infusing mouse and human sCD6 by different systemic routes, either alone or as adjunctive therapy to gold standard antibiotics, in a lethal model of polymicrobial sepsis. To this end, C57BL/6 mice undergoing high-grade septic shock induced by cecal ligation and puncture (CLP; ≥90% lethality) were infused via the intraperitoneal (i.p.) or intravenous (i.v.) route with shCD6 at different doses and time points, either alone or in combination with imipenem/cilastatin (I/C) at a dose of 33 mg/kg of body weight every 8 h. Significantly reduced mortality and proinflammatory cytokine levels were observed by i.p. infusion of a single shCD6 dose (1.25 mg/kg) 1 h pre- or post-CLP. When using the i.v. route, mice survival was significantly extended by starting shCD6 infusion at later time points post-CLP (up to 6 h after CLP). Significant adjunctive effects on mouse survival were observed by i.p. or i.v. infusion of shCD6 in combination with i.p. I/C post-CLP. Similar results were obtained in mice expressing high sustained levels (5 to 10 μg/ml) of mouse sCD6 in serum by means of transduction with hepatotropic adeno-associated virus (AAV). Taken together, the data support the conserved antibacterial effects of human and mouse sCD6 and their use as adjunctive therapy in experimental models of complex and severe polymicrobial sepsis.

Topics: Animals; Anti-Bacterial Agents; Antigens, CD; Antigens, Differentiation, T-Lymphocyte; Cecum; Cilastatin; Cilastatin, Imipenem Drug Combination; Cytokines; Dependovirus; Disease Models, Animal; Drug Combinations; Gram-Negative Bacteria; Gram-Positive Bacteria; Humans; Imipenem; Ligation; Male; Mice; Mice, Inbred C57BL; Receptors, Scavenger; Sepsis

The identification of the optimal agent for administration via the respiratory tract when treating pneumonia caused by carbapenem-resistant Acinetobacter baumannii (CRAB).. A murine model of acute CRAB pneumonia was established by intratracheal (i.t.) inoculation with 2.5 × 10⁷ colony-forming units (CFU) of A. baumannii strain Ab396 plus 10% porcine mucin. After 4h the infected BALB/c mice were treated intratracheally with 25μl of either 0.85% saline (control group), colistimethate sodium (CMS) (166 666 U/kg, CMS group), imipenem/cilastatin (30/30 mg/kg, imipenem group), or meropenem (20mg/kg, meropenem group), every 8h. The therapeutic efficacy of these agents was examined.. A. baumannii strain Ab396 was susceptible to CMS only. However, meropenem treatment did give a significantly superior survival rate (100%) compared to treatment with imipenem (50%), CMS (33%), or saline (0%) (p<0.001 vs. the control and CMS groups, p=0.006 vs. the imipenem group, by log-rank test). Furthermore, compared to the other groups, the meropenem group demonstrated significantly more favorable results in terms of tissue penetration of the antibiotic, bacterial clearance, normalization of the wet lung-to-body weight ratio, and down-regulation of pro-inflammatory cytokine levels in the lungs.. Administration of meropenem via the respiratory tract proved to have the best therapeutic efficacy among the antibiotics tested when treating advanced murine CRAB pneumonia.

Topics: Acinetobacter baumannii; Acinetobacter Infections; Acute Disease; Animals; Anti-Bacterial Agents; Carbapenems; Cilastatin; Cilastatin, Imipenem Drug Combination; Colistin; Cytokines; Disease Models, Animal; Drug Combinations; Drug Resistance, Bacterial; Female; Imipenem; Meropenem; Mice; Mice, Inbred BALB C; Microbial Sensitivity Tests; Pneumonia, Bacterial; Stem Cells; Thienamycins

Efficacy of panipenem/betamipron (PAPM/BP) against experimental pneumonia caused by penicillin-resistant Streptococcus pneumoniae (PRSP: MIC of benzylpenicillin, > or = 1.56 micrograms/ml) in mice was compared with those of imipenem/cilastatin (IPM/CS), meropenem (MEPM), cefozopran (CZOP), ceftriaxone (CTRX), ampicillin (ABPC), and vancomycin (VCM). The infection was induced by inoculating a PRSP clinical isolate, 9601 (serotype 6) or 10,693 (serotype 19), into ddY male mice intranasally. Drugs were administered subcutaneously at doses of 0.4, 2, and 10 mg/kg, 18, 26, 42, and 50 hours post-infection. Viable cell counts in the lungs were determined 66 hours post-infection. PAPM/BP showed the greatest efficacy against the infections among tested drugs. MICs of PAPM against PRSP 9601 and 10,693 were both 0.125 microgram/ml, which were superior to those of IPM (0.25 and 0.5 microgram/ml, respectively), MEPM (0.5 and 1 microgram/ml, respectively), CZOP (2 and 1 microgram/ml, respectively), CTRX (both 1 microgram/ml), ABPC (both 4 micrograms/ml), and VCM (0.5 and 0.25 microgram/ml, respectively). These results suggest that the potent in vivo activity of PAPM/BP reflects the potent in vitro activity of PAPM. MICs of PAPM, IPM, MEPM, and CZOP against clinical isolates, penicillin-susceptible S. pneumoniae (PSSP: MIC of benzylpenicillin, < or = 0.05 microgram/ml), penicillin-intermediate S. pneumoniae (PISP: MIC of benzylpenicillin, 0.1-0.78 microgram/ml), and PRSP, were tested by an agar dilution method. MIC90s of the drugs against the PSSP, PISP, and PRSP were as follows: PAPM, 0.012, 0.05, and 0.39 microgram/ml; IPM, < or = 0.006, 0.1, and 0.78 microgram/ml; MEPM, 0.05, 0.39, and 1.56 micrograms/ml; and CZOP, 0.2, 0.78, and 6.25 micrograms/ml, respectively. Thus, PAPM showed the most potent activity among tested drugs against clinical isolates of PISP and PRSP.

Topics: Ampicillin; Animals; beta-Alanine; Cefozopran; Ceftriaxone; Cephalosporins; Cilastatin; Cilastatin, Imipenem Drug Combination; Disease Models, Animal; Drug Combinations; Drug Resistance; Imipenem; Male; Meropenem; Mice; Mice, Inbred Strains; Penicillin Resistance; Pneumonia, Pneumococcal; Streptococcus pneumoniae; Thienamycins; Vancomycin

The present study addressed the role of IL-12 in a murine model of septic peritonitis, induced by cecal ligation and puncture (CLP). Although CLP surgery induced IL-12 production at 6 and 24 h after surgery, IL-12 immunoneutralization was clearly deleterious in this model: 54% of CLP mice receiving preimmune serum survived, whereas mice administered IL-12 antisera prior to CLP experienced a 25% survival rate. IL-12 immunoneutralization not only led to increased mortality, but also appeared to promote a shift away from IL-12 and IFN-gamma, in favor of IL-10. This cytokine shift corresponded to changes in bacterial load, as CLP mice receiving IL-12 antiserum yielded more CFUs from the peritoneal cavity at 24 h after CLP. To address the role of bacterial infection in IL-12 antiserum-induced mortality following CLP, antibiotics were administered for 4 days after surgery. Despite regular antibiotic administration, IL-12 immunoneutralization still reduced survival in CLP mice. Furthermore, histology of the ceca revealed that mice administered IL-12 antisera failed to show typical organization of the damaged cecum wall. Accordingly, Gram staining revealed bacteria within peritoneal fluids from these mice, while peritoneal fluids from CLP mice that received preimmune serum and antibiotics were free of bacteria. Altogether, these data suggested multiple important roles for IL-12 in the evolution of murine septic peritonitis.

Topics: Acute Disease; Animals; Cecal Diseases; Cilastatin; Cilastatin, Imipenem Drug Combination; Disease Models, Animal; Drug Combinations; Drug Therapy, Combination; Female; Fibrosis; Imipenem; Immune Sera; Immunization, Passive; Interferon-gamma; Interleukin-10; Interleukin-12; Intestinal Perforation; Ligation; Mice; Peritoneum; Peritonitis; Sepsis; Wound Healing

The effect of antibiotics on the acute lung injury induced by virulent Pseudomonas aeruginosa PA103 was quantitatively analyzed in a rat model. Lung injury was induced by the instillation of PA103 directly into the right lower lobes of the lungs of anesthetized rats. The alveolar epithelial injury, extravascular lung water, and total plasma equivalents were measured as separate, independent parameters of acute lung injury. Four hours after the instillation of PA103, all the parameters were increased linearly depending on the dose of P. aeruginosa. Next, we examined the effects of intravenously administered antibiotics on the parameters of acute lung injury in D-galactosamine-sensitized rats. One hour after the rats received 10(7) CFU of PA103, an intravenous bolus injection of aztreonam (60 mg/kg) or imipenem-cilastatin (30 mg/kg) was administered. Despite an MIC indicating resistance, imipenem-cilastatin improved all the measurements of lung injury; in contrast, aztreonam, which had an MIC indicating sensitivity, did not improve any of the lung injury parameters. The antibiotics did not generate different quantities of plasma endotoxin; therefore, endotoxin did not appear to explain the differences in lung injury. This in vivo model is useful to quantitatively compare the efficacies of parenteral antibiotic administration on Pseudomonas airspace infections.

Topics: Animals; Aztreonam; Cilastatin; Cilastatin, Imipenem Drug Combination; Disease Models, Animal; Drug Combinations; Drug Therapy, Combination; Imipenem; Lung Diseases; Male; Microbial Sensitivity Tests; Monobactams; Pseudomonas aeruginosa; Pseudomonas Infections; Rats; Rats, Sprague-Dawley

A deep-seated Pseudomonas aeruginosa mouse kidney abscess model was used to compare the therapeutic efficacy of clinafloxacin, a fluoroquinolone in clinical trials, with that of clinically relevant standard drugs. Following 50 mg/kg oral doses, twice daily for five consecutive days, clinafloxacin produced a 4 log decrease in mean bacterial count, the greatest decrease of all drugs tested. The same dosage regimen resulted in complete bacterial eradication in 88% of the kidneys. No other compound produced total bacterial clearance in 50% of the kidneys at the highest dose tested.

Topics: Abscess; Animals; Anti-Infective Agents; Area Under Curve; Ceftazidime; Cilastatin; Cilastatin, Imipenem Drug Combination; Ciprofloxacin; Colony Count, Microbial; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Combinations; Drug Therapy, Combination; Female; Fluoroquinolones; Half-Life; Imipenem; Kidney; Kidney Diseases; Mice; Microbial Sensitivity Tests; Pseudomonas aeruginosa; Pseudomonas Infections; Quinolones; Treatment Outcome

Inhibition of nitric oxide synthesis was investigated in a murine model of advanced sepsis in which antibiotic therapy alone did not improve survival. Seven hours after receiving a lethal intraperitoneal challenge with live Escherichia coli, mice were given either NG-monomethyl-L-arginine (L-NMMA) intravenously, imipenem-cilastatin subcutaneously or a combination of both. L-NMMA (3-300 mg/kg) or imipenem-cilastatin (10 or 50 mg/kg) given alone did not improve survival; co-administration of L-NMMA and either 10 or 50 mg imipenem-cilastatin/kg improved survival significantly. These findings suggest that nitric oxide contributes to the morbidity associated with advanced sepsis and that nitric oxide synthase inhibition may improve the efficacy of conventional antimicrobial treatment of severe infections.

Topics: Amino Acid Oxidoreductases; Animals; Arginine; Cilastatin; Cilastatin, Imipenem Drug Combination; Disease Models, Animal; Drug Combinations; Drug Therapy, Combination; Escherichia coli Infections; Imipenem; Male; Mice; Nitric Oxide Synthase; omega-N-Methylarginine; Peritonitis

Cefamandole, cefoxitin, cefotetan, ceftizoxime, imipenem plus cilastatin, and ampicillin plus sulbactam were compared in the eradication of subcutaneous abscess in mice caused by Bacteroides fragilis group organisms and Escherichia coli alone or in combination. The abscesses were examined 5 d after inoculation. B. fragilis group reached log10.1-11.0 organisms per abscess and E. coli log11.6-12.5. Imipenem plus cilastatin significantly reduced (in 6.9-10.6 logs) the number of E. coli and all members of B. fragilis group alone or in all combinations. Ampicillin plus sulbactam reduced the numbers of all B. fragilis group (in 4.2-7.2 logs) but was less effective against E. coli (reduction of 1.8-4.2 logs). Cefoxitin was effective in significantly reducing (in 4.9-6.2 logs) the number of E. coli and all members of B. fragilis group alone or in all combinations. Cefotetan was effective against B. fragilis (reduction of 5.1-6.6 logs) and E. coli alone or in combination but did not reduce the number of Bacteroides thetaiotaomicron, Bacteroides vulgatus, and Bacteroides ovatus. Ceftizoxime was effective against only B. ovatus (reduction of 3.7-5.8) and E. coli (reduction of 6.0-8.1 logs); it did not reduce the number of other organisms. Cefamandole was effective against only E. coli and was not effective against any member of the B. fragilis group. These in vivo data confirm the in vitro activity of these antimicrobials.

Topics: Abscess; Ampicillin; Animals; Anti-Bacterial Agents; Bacteroides fragilis; Bacteroides Infections; Cefamandole; Cefotetan; Cefoxitin; Ceftizoxime; Cilastatin; Cilastatin, Imipenem Drug Combination; Disease Models, Animal; Drug Combinations; Drug Therapy, Combination; Escherichia coli; Escherichia coli Infections; Imipenem; Male; Mice; Skin Diseases; Sulbactam

The beta-lactam antibiotics imipenem-cilastatin, BMY-26225, and cefazolin significantly lowered the convulsive threshold of pentylenetetrazole in mice. In addition, imipenem-cilastatin and cefazolin were found to inhibit 3H-labeled gamma-aminobutyric acid binding to synaptic membranes from rat brains. Our results suggest that the pentylenetetrazole convulsive model may be useful in evaluating the proconvulsive liabilities of new carbapenems and other beta-lactam antibiotics and that the mechanism of imipenem-cilastatin and cefazolin toxicity may involve interaction with gamma-aminobutyric acid receptors.

Topics: Animals; Anti-Bacterial Agents; beta-Lactams; Binding, Competitive; Cefazolin; Cilastatin; Cilastatin, Imipenem Drug Combination; Cyclopropanes; Disease Models, Animal; Drug Combinations; gamma-Aminobutyric Acid; Imipenem; Lactams; Male; Mice; Pentylenetetrazole; Seizures; Thienamycins