agar and Pseudomonas-Infections

Tolerance to antibiotics may occur due to changes in bacterial growth patterns and can be a precursor to development of resistance. However, there is a lack of information on the ability of ocular bacteria isolates to develop tolerance. This paper explores the tolerance to 8 different antibiotics of 61 microbial keratitis isolates of Pseudomonas aeruginosa from Australia and India using the MBC/MIC ratio, with tolerance defined by a ratio ≥ 32, and tolerance to ciprofloxacin by an agar diffusion assay.. Antibiotics used were ciprofloxacin, levofloxacin, gentamicin, tobramycin, piperacillin, imipenem, ceftazidime and polymyxin B. Isolates were sourced from microbial keratitis infections in Australia and India. Minimum bactericidal and minimum inhibitory concentration (MBC and MIC) were obtained using broth microdilution and compared to breakpoints from the Clinical Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) to determine bacterial susceptibility. Tolerance was assessed as MBC/MIC ≥ 32. An alternative method for tolerance detection (TD) was assessed with 13P. aeruginosa sensitive isolates by agar disk diffusion assay of ciprofloxacin followed by application of glucose to the agar and observation of re-growth of colonies.. Thirty-three isolates were resistant to imipenem, 20 to ciprofloxacin, 14 to tobramycin and piperacillin, 12 to levofloxacin and ceftazidime, 8 to gentamicin, and 5 to polymyxin B. The percentage of strains resistant to levofloxacin (7 vs 30 %; p = 0.023), gentamicin (0 vs 24 %; p = 0.005) and tobramycin (4 vs 33 %; p = 0.004) was significantly greater in isolates from India.On average, strains from India exhibited notably greater MIC and MBC values compared to strains obtained from Australia. Out of 61 isolates, none displayed an MBC/MIC ratio ≥ 32. However, three sensitive isolates had low tolerance, nine had medium tolerance and one had high tolerance to ciprofloxacin with the TDtest.. This study used two methods to determine whether P. aeruginosa strains could show tolerance to antibiotics. Using the MBC/MIC criteria no strain was considered tolerant to any of the eight antibiotics used. When 13 strains were tested for tolerance against ciprofloxacin, the most commonly used monotherapy for keratitis, one had high tolerance and nine had medium tolerance. This demonstrates the capacity of P. aeruginosa to develop tolerance which may result in therapeutic failures if inappropriate dosing regimens are used to treat keratitis.

Topics: Agar; Anti-Bacterial Agents; Ceftazidime; Ciprofloxacin; Gentamicins; Humans; Imipenem; Keratitis; Levofloxacin; Microbial Sensitivity Tests; Piperacillin; Polymyxin B; Pseudomonas aeruginosa; Pseudomonas Infections; Tobramycin

Topics: Agar; Anti-Bacterial Agents; beta-Lactamases; Clone Cells; Colistin; Humans; Microbial Sensitivity Tests; Pseudomonas aeruginosa; Pseudomonas Infections

Animal models of chronic lung infection with P. aeruginosa (PA) are useful tools to improve antibiotic (ATB) treatment. Two main models based on the pulmonary instillation of PA embedded in agar or calcium-alginate beads are currently used. However, these two polymers used to prepare the beads have different properties; for example, agar is a neutral polysaccharide while alginate is anionic. We hypothesized that the effect of an ATB on PA entrapped in agar or calcium-alginate beads depends on its physicochemical properties, including charge, and concentration. To test this hypothesis, PAs were entrapped in agar or calcium-alginate beads dispersed in a growth medium containing either tobramycin (TOB), selected as a cationic ATB, or ciprofloxacin (CIP) selected as a neutral zwitterionic ATB. In vitro, time-kill curves evaluating the efficacy of ATBs over time were performed by measuring the light emitted by a bioluminescent PA for 42 h in the presence of ATB concentrations ranging from 0 to 100 times the MIC. In the presence of CIP, time-kill curves obtained with PA trapped in agar or calcium-alginate beads were comparable, whatever the CIP concentration used. In the presence of TOB, a clear difference was observed between the kill curves obtained with PA embedded in agar or calcium-alginate beads. While PA trapped within agar displayed the same susceptibility than the planktonic one, it was unresponsive to TOB for concentrations up to 1-fold MIC when trapped in calcium-alginate. At 10-fold the TOB's MIC, the luminescence emitted by PA01 in the agar beads was reduced by 95% after 40 h, whereas it returned to the same initial value for PA01 trapped in alginate-based beads. The reduction in TOB efficiency was even greater when alginate-based beads were dispersed in a mucus-simulating medium. These results show that the agar and alginate beads models can be interchangeable only for uncharged ATB, such as CIP, but not for cationic ATB, like TOB. In vitro experiments performed in this study could be a quick way to evaluate the effect of each model on a given ATB before performing animal experiments.

Topics: Agar; Alginates; Animals; Anti-Bacterial Agents; Ciprofloxacin; Disease Models, Animal; Lung; Pseudomonas aeruginosa; Pseudomonas Infections; Respiratory Tract Infections; Tobramycin

No single material can provide all requirements for wound dressings. Here, we evaluated the influence of different soy protein isolate and agar proportions (3:1, 1:1, and 1:3) in blend films on some of their physical-chemical and antibacterial properties to elucidate their potential as wound dressings. The films were synthesized by the gel casting method and ciprofloxacin hydrochloride was incorporated into the films. Films were characterized based on their surface morphology, water uptake ability, and weight loss profile. Also, the ciprofloxacin hydrochloride release kinetics was quantified spectrophotometrically. The antibacterial effect was evaluated against Staphylococcus aureus and Pseudomonas aeruginosa strains. The soy protein isolate-agar ratio affected the water uptake of the films and the release profile of ciprofloxacin hydrochloride but not the weight loss profile. The amount of drug released decreased near 80% because of the decrease in agar content in the films. The release kinetics of ciprofloxacin hydrochloride data best fitted to the Korsmeyer-Peppas model, suggesting that the mechanism of drug release was mainly of the diffusion type. All ciprofloxacin hydrochloride-releasing soy protein isolate-agar films strongly inhibited the cell viability of the bacterial strains studied. We concluded that water uptake and ciprofloxacin hydrochloride release can be controlled by changing the soy protein isolate-agar proportion. The proportions did not lead to changes in the antibacterial strength of the films.

Topics: Agar; Anti-Bacterial Agents; Bandages; Ciprofloxacin; Drug Carriers; Drug Delivery Systems; Drug Liberation; Humans; Pseudomonas aeruginosa; Pseudomonas Infections; Soybean Proteins; Staphylococcal Infections; Staphylococcus aureus; Wound Healing

Topics: Agar; Burkholderia cenocepacia; Burkholderia Infections; Cell Culture Techniques; Culture Media; Cystic Fibrosis; Humans; Pseudomonas aeruginosa; Pseudomonas Infections; Sputum

Murine models of acute and chronic lung infection have been used in studying Pseudomonas aeruginosa for assessing in vivo behavior and for monitoring of the host response. These models provide an important resource for studies of the initiation and maintenance of bacterial infection, identify bacterial genes essential for in vivo maintenance and for the development and testing of new therapies. The rat has been used extensively as a model of chronic lung infection, whereas the mouse has been a model of acute and chronic infection. Intratracheal administration of planktonic bacterial cells in the mouse provides a model of acute pneumonia. Bacteria enmeshed in agar beads can be used in the rat and mouse to reproduce the lung pathology of cystic fibrosis patients with advanced chronic pulmonary disease. Here, we describe the methods to assess virulence of P. aeruginosa using prototype and clinical strains in the Sprague-Dawley rat and the C57BL/6NCrlBR mouse by monitoring several measurable read-outs including weight loss, mortality, in vivo growth curves, the competitive index of infectivity, and the inflammatory response.

Topics: Acute Disease; Agar; Animals; Biological Assay; Chronic Disease; Colony Count, Microbial; Disease Models, Animal; Host-Pathogen Interactions; Inflammation; Kinetics; Lung; Male; Mice, Inbred C57BL; Pseudomonas aeruginosa; Pseudomonas Infections; Rats, Sprague-Dawley; Respiratory Tract Infections; Survival Analysis; Virulence

Infections associated with health care services are nowadays widespread and, associated to the progressive emergence of microorganisms resistant to conventional chemical antibiotics, are major causes of morbidity and mortality. One of the most representative microorganisms in this scenario is the bacterium Pseudomonas aeruginosa, which alone is responsible for ca. 13-15% of all nosocomial infections. Bacteriophages have been reported as a potentially useful tool in the diagnosis of bacterial diseases, since they specifically recognize and lyse bacterial isolates thus confirming the presence of viable cells. In the present research effort, immobilization of these biological (although metabolically inert) entities was achieved via entrapment within (optimized) porous (bio)polymeric matrices of alginate and agar, aiming at their full structural and functional stabilization. Such phage-impregnated polymeric matrices are intended for future use as chromogenic hydrogels sensitive to color changes evolving from reaction with (released) intracytoplasmatic moieties, as a detection kit for P. aeruginosa cells.

Topics: Agar; Alginates; Bacteriological Techniques; Biopolymers; Biosensing Techniques; Cells, Immobilized; Cross Infection; Glucuronic Acid; Hexuronic Acids; Humans; Hydrogels; Pseudomonas aeruginosa; Pseudomonas Infections; Pseudomonas Phages

Pseudomonas aeruginosa is an opportunistic pathogen that can adapt to changing environments and can secrete an exopolysaccharide known as alginate as a protection response, resulting in a colony morphology and phenotype referred to as mucoid. However, how P. aeruginosa senses its environment and activates alginate overproduction is not fully understood. Previously, we showed that Pseudomonas isolation agar supplemented with ammonium metavanadate (PIAAMV) induces P. aeruginosa to overproduce alginate. Vanadate is a phosphate mimic and causes protein misfolding by disruption of disulfide bonds. Here we used PIAAMV to characterize the pathways involved in inducible alginate production and tested the global effects of P. aeruginosa growth on PIAAMV by a mutant library screen, by transcriptomics, and in a murine acute virulence model. The PA14 nonredundant mutant library was screened on PIAAMV to identify new genes that are required for the inducible alginate stress response. A functionally diverse set of genes encoding products involved in cell envelope biogenesis, peptidoglycan remodeling, uptake of phosphate and iron, phenazine biosynthesis, and other processes were identified as positive regulators of the mucoid phenotype on PIAAMV. Transcriptome analysis of P. aeruginosa cultures growing in the presence of vanadate showed differential expression of genes involved in virulence, envelope biogenesis, and cell stress pathways. In this study, it was observed that growth on PIAAMV attenuates P. aeruginosa in a mouse pneumonia model. Induction of alginate overproduction occurs as a stress response to protect P. aeruginosa, but it may be possible to modulate and inhibit these pathways based on the new genes identified in this study.

Topics: Acute Disease; Agar; Alginates; Animals; Bacterial Proteins; Culture Media; Disease Models, Animal; Gene Expression Profiling; Gene Expression Regulation, Bacterial; Glucuronic Acid; Heat-Shock Response; Hexuronic Acids; Humans; Mice; Molecular Sequence Data; Oligonucleotide Array Sequence Analysis; Pneumonia, Bacterial; Pseudomonas aeruginosa; Pseudomonas Infections; Vanadates; Virulence

The broth microdilution method for fosfomycin and Pseudomonas aeruginosa was assessed and compared with the approved agar dilution method in 206 genetically unrelated P. aeruginosa clinical isolates. Essential agreement between the two methods was 84%, and categorical agreement was 89.3%. Additionally, Etest and disk diffusion assays were performed. Results validate broth microdilution as a reliable susceptibility testing method for fosfomycin against P. aeruginosa. Conversely, unacceptable concordance was established between Etest and disk diffusion results with agar dilution results.

Topics: Agar; Anti-Bacterial Agents; Culture Media; Fosfomycin; Humans; Linear Models; Microbial Sensitivity Tests; Pseudomonas aeruginosa; Pseudomonas Infections

North American ginseng is known to have immunomodulatory and antipseudomonal properties in vitro. In this study we investigated the effects of aqueous ginseng extract, either alone or in a combination with the antibiotic tobramycin, in an animal model of chronic Pseudomonas aeruginosa lung infection. The lungs of male rats (n = 5) were infected with P. aeruginosa (2 × 10(8) cfu/mL) in agar-beads by intratracheal instillation. Starting on day 7 post-infection, animals were treated daily for 3 consecutive days with saline, tobramycin (300 μg/kg body mass, intratracheal), and (or) ginseng (100 mg/kg body mass, subcutaneous); animals were sacrificed 24 h after the third drug treatment. Lung bacteria counts, cytokine levels in sera, and lung histopathology were examined. The treatment of infected animals with tobramycin [6.6 × 10(4) colony forming units (cfu)], ginseng (5.3 × 10(4) cfu), or tobramycin plus ginseng (2.0 × 10(3) cfu) lessened the lung infection compared with the control group (saline treated) (6.0 × 10(6) cfu). The levels of pro-inflammatory cytokines (IL-2, IL-4, IL-6, IL-12p70, IFN-γ, GM-CSF, TNF-α) in infected animals were significantly increased with co-treatment of ginseng plus tobramycin. These data suggest that co-administration of aqueous ginseng extract and tobramycin stimulated the pro-inflammatory response and promoted the killing of P. aeruginosa.

Topics: Agar; Animals; Anti-Bacterial Agents; Bacterial Load; Body Weight; Chemokines; Culture Media; Cytokines; Inflammation; Lung; Lung Diseases; Male; Organ Size; Panax; Plant Extracts; Pseudomonas aeruginosa; Pseudomonas Infections; Rats; Rats, Sprague-Dawley; Tobramycin

Pseudomonas aeruginosa is a Gram-negative bacterium that causes various opportunistic infections. Chronic and intractable infections with P. aeruginosa are closely related to the high levels of resistance displayed by this organism to antimicrobial agents and its ability to form biofilms. Although the standard method for examining antimicrobial resistance involves susceptibility testing using Mueller-Hinton agar or broth, this method does not take into account the influence of biofilm formation on antimicrobial susceptibility. Poloxamer 407 is a hydrophilic, nonionic surfactant of the more general class of copolymers that can be used to culture bacteria with similar properties as cells in a biofilm environment. Therefore, the aim of this study was to compare the antimicrobial susceptibility of bacteria cultured in Poloxamer 407 gel to those grown on Mueller-Hinton agar using the Kirby-Bauer disk diffusion method with 24 strains of P. aeruginosa. Antimicrobial sensibility differed between the two mediums, with >60% of the strains displaying increased resistance to β-lactams when cultured on Poloxamer 407 gel. In addition, scanning electron microscopy revealed that typical biofilm formation and extracellular polymeric substance production was only observed with bacteria grown on Poloxamer 407 gel. Therefore, antimicrobial susceptibility test using Poloxamer 407 gel may provide more accurate information and allow the selection of suitable antimicrobial agents for treating patients infected with biofilm-forming pathogens.

Topics: Agar; Anti-Bacterial Agents; Biofilms; Culture Media; Disk Diffusion Antimicrobial Tests; Gels; Humans; Microbial Sensitivity Tests; Microscopy, Electron, Scanning; Poloxamer; Pseudomonas aeruginosa; Pseudomonas Infections; Surface-Active Agents

We sought to characterise a refined rat model of respiratory infection with P. aeruginosa over an acute time course and test the antibiotic ciprofloxacin.. Agar beads were prepared ± SPAN(®)80. Rats were inoculated with sterile agar beads or those containing 10(5) colony forming units (cfu) P. aeruginosa via intra-tracheal dosing. Bacterial load and inflammatory parameters were measured.. Differing concentrations of SPAN(®) 80 modified median agar bead diameter and reduced particle size distribution. Beads prepared with 0.01% v/v SPAN(®)80 were evaluated in vivo. A stable lung infection up to 7 days post infection was achieved and induced BALF neutrophilia 2 and 5 days post infection. Ciprofloxacin (50mg/kg) significantly attenuated infection without affecting the inflammatory parameters measured.. SPAN(®) 80 can control the particle size and lung distribution of agar beads and P. aeruginosa-embedded beads prepared with 0.01%v/v SPAN(®)80 can induce infection and inflammation over 7 days.

Topics: Acute Disease; Agar; Animals; Anti-Infective Agents; Bacterial Load; Bronchoalveolar Lavage Fluid; Ciprofloxacin; Disease Models, Animal; Hexoses; Leukocyte Count; Male; Microspheres; Neutrophils; Particle Size; Pseudomonas aeruginosa; Pseudomonas Infections; Rats; Rats, Sprague-Dawley; Respiratory Tract Infections; Time Factors; Treatment Outcome

The stringent response is a regulatory system that allows bacteria to sense and adapt to nutrient-poor environments. The central mediator of the stringent response is the molecule guanosine 3',5'-bispyrophosphate (ppGpp), which is synthesized by the enzymes RelA and SpoT and which is also degraded by SpoT. Our laboratory previously demonstrated that a relA mutant of Pseudomonas aeruginosa, the principal cause of lung infections in cystic fibrosis patients, was attenuated in virulence in a Drosophila melanogaster feeding model of infection. In this study, we examined the role of spoT in P. aeruginosa virulence. We generated an insertion mutation in spoT within the previously constructed relA mutant, thereby producing a ppGpp-devoid strain. The relA spoT double mutant was unable to establish a chronic infection in D. melanogaster and was also avirulent in the rat lung agar bead model of infection, a model in which the relA mutant is fully virulent. Synthesis of the virulence determinants pyocyanin, elastase, protease, and siderophores was impaired in the relA spoT double mutant. This mutant was also defective in swarming and twitching, but not in swimming motility. The relA spoT mutant and, to a lesser extent, the relA mutant were less able to withstand stresses such as heat shock and oxidative stress than the wild-type strain PAO1, which may partially account for the inability of the relA spoT mutant to successfully colonize the rat lung. Our results indicate that the stringent response, and SpoT in particular, is a crucial regulator of virulence processes in P. aeruginosa.

Topics: Agar; Animals; Bacterial Load; Bacterial Proteins; Disease Models, Animal; Drosophila melanogaster; Feeding Behavior; Gene Expression Regulation, Bacterial; Guanosine Pentaphosphate; Heat-Shock Response; Humans; Ligases; Lung; Mutation; Pseudomonas aeruginosa; Pseudomonas Infections; Rats; Virulence

Topics: Agar; Anti-Bacterial Agents; Culture Media; Drug Resistance, Multiple, Bacterial; Fosfomycin; Humans; Microbial Sensitivity Tests; Pseudomonas aeruginosa; Pseudomonas Infections

Metallo beta-lactamase (MBL)-mediated resistance to carbapenems is an emerging threat in hospital isolates of Pseudomonas aeruginosa. Though there are several screening methods to detect this enzyme production, the National Committee for Clinical Laboratory Standards (NCCLS) does not have performance standards documented so far. There is not enough information from the Indian subcontinent regarding the prevalence and the screening methods for these enzymes. The present study was undertaken to detect MBL in nosocomial isolates of P. aeruginosa by two screening methods.. Fifty consecutive P. aeruginosa isolates obtained from hospitalized patients were subjected to susceptibility testing to antipseudomonal drugs by disc diffusion, and minimum inhibitory concentration (MIC) of imipenem was determined. The production of MBL was detected by 4-fold reduction in MIC with imipenem-ethylene diamine tetraacetic acid (EDTA) and the zone size enhancement with EDTA impregnated imipenem and ceftazidime discs.. Sixteen per cent of the isolates tested were resistant to imipenem by disc diffusion method of which 87.5 per cent exhibited a zone size enhancement with EDTA impregnated imipenem and ceftazidime discs as well as a 4-fold reduction in MIC with imipenem EDTA. The imipenem susceptible isolates (84%) had normal MIC values and exhibited no zone diameter enhancement with EDTA impregnated antibiotic discs.. MBL-mediated imipenem resistance in P. aeruginosa is a cause for concern in the therapy of critically ill patients. The two confirmatory methods i.e., zone diameter enhancement with EDTA impregnated imipenem and ceftazidime discs and 4-fold reduction in MIC with imipenem EDTA combination are equally effective for their detection.

Topics: Agar; Anti-Bacterial Agents; beta-Lactamases; Carbapenems; Ceftazidime; Edetic Acid; Hospitals; Humans; Imipenem; Microbial Sensitivity Tests; Pseudomonas aeruginosa; Pseudomonas Infections

Extracellular bacterial pathogens such as Pseudomonas aeruginosa are able to penetrate into host tissues (given an initial breech in the outer barrier, e.g. a wound) through the action of exo-toxins and degradative exo-enzymes. A mathematical model of this process is presented which, in the absence of significant immune response, predicts the progression of the bacteria into the tissue as a travelling wave whose velocity can be determined explicitly in terms of the model parameters. Simple in vitro experiments in protein-based matrices are performed which yield results consistent with this behaviour. A complementary in vitro experimental system with distinct qualitative behaviour is also studied, giving further insight and confidence in the modelling approach.

Topics: Agar; Bacteria; Bacterial Infections; Extracellular Matrix; Gelatin; Humans; In Vitro Techniques; Mathematics; Models, Biological; Pseudomonas aeruginosa; Pseudomonas Infections; Wound Infection

Repeated challenge with antigen is involved in the pathogenesis of a variety of pulmonary diseases. Patients with cystic fibrosis (CF) experience recurrent pulmonary colonization with Pseudomonas aeruginosa before establishment of chronic lung infection. To mimic recurrent lung infections in CF patients, the lungs of susceptible BALB/c mice were re-infected with P. aeruginosa 14 days after the initial infection. Singly-infected BALB/c mice, as well as non-infected mice, were used as controls. Decreased mortality and milder lung inflammation in re-infected BALB/c mice, as well as a tendency for improved clearance of bacteria, was observed when compared with singly-infected mice. The improved outcome in re-infected mice correlated with changes in CD4 cell numbers. Surface expression of LFA-1 on pulmonary CD4 cells was increased in re-infected compared with singly-infected mice. Moreover, resistance to re-infection was paralleled by a shift towards a Th1-dominated response and increased IL-12 production. No significant increase in serum IgG was observed in the re-infected mice. In conclusion, these results indicate a protective role for a Th1-dominated response, independent of antibody production, in chronic P. aeruginosa lung infection in CF.

Topics: Agar; Alginates; Animals; Antibodies, Bacterial; Bronchoalveolar Lavage Fluid; CD4 Lymphocyte Count; Chronic Disease; Cytokines; Female; Glucuronic Acid; Hexuronic Acids; Immunoglobulin G; Interferon-gamma; Interleukin-12; Interleukin-4; Lymphocyte Function-Associated Antigen-1; Mice; Mice, Inbred BALB C; Models, Animal; Pneumonia, Bacterial; Pseudomonas aeruginosa; Pseudomonas Infections; Recurrence; Th1 Cells

Pseudomonas aeruginosa is the most common pathogen infecting the lungs of patients with cystic fibrosis (CF). Improved antimicrobial chemotherapy has significantly increased the life expectancy of these patients. However, accurate susceptibility testing of P. aeruginosa isolates from CF sputum may be difficult because the organisms are often mucoid and slow growing. This study of 597 CF isolates of P. aeruginosa examined the correlation of disk diffusion and Etest (AB BIODISK, Solna, Sweden) results with a reference broth microdilution method. The rates of interpretive errors for 12 commonly used antipseudomonal antimicrobials were determined. The disk diffusion method correlated well (zone diameter versus MIC) for all of the agents tested. However, for mucoid isolates, correlation coefficients (r values) for piperacillin, piperacillin-tazobactam, and meropenem were <0.80. The Etest correlation with reference broth microdilution results (MIC versus MIC) was acceptable for all of the agents tested, for both mucoid and nonmucoid isolates. Category interpretation errors were similar for the disk diffusion and Etest methods with 0.4 and 0.1%, respectively, very major errors (false susceptibility) and 1.1 and 2.2% major errors (false resistance). Overall, both agar diffusion methods appear to be broadly acceptable for routine clinical use in susceptibility testing of CF isolates of P. aeruginosa.

Topics: Agar; Anti-Bacterial Agents; Child; Cystic Fibrosis; Humans; Lung; Lung Diseases; Microbial Sensitivity Tests; Pseudomonas aeruginosa; Pseudomonas Infections; Reproducibility of Results; Sputum

The aim of the study was to evaluate the effects of two kinds of Chinese medicinal herbs, Isatis tinctoria L (ITL) and Daphne giraldii Nitsche (DGN), on a rat model of chronic Pseudomonas aeruginosa lung infection mimicking cystic fibrosis (CF). Compared to the control group, both drugs were able to reduce the incidence of lung abscess (p < 0.05) and to decrease the severity of the macroscopic pathology in lungs (p < 0.05). In the great majority of the rats, the herbs altered the inflammatory response in the lungs from an acute type inflammation, dominated by polymorphonuclear leukocytes (PMN), to a chronic type inflammation, dominated by mononuclear leukocytes (MN). DGN also improved the clearance of P. aeruginosa from the lungs (p < 0.03) compared with the control group. There were no significant differences between the control group and the two herbal groups with regard to serum IgG and IgA anti-P. aeruginosa sonicate antibodies. However, the IgM concentration in the ITL group was significantly lower than in the control group (p < 0.03). These results suggest that the two medicinal herbs might be helpful to CF patients with chronic P. aeruginosa lung infection, DGN being the most favorable.

Topics: Agar; Animals; Antibodies, Bacterial; Chronic Disease; Culture Media; Cystic Fibrosis; Disease Models, Animal; Drugs, Chinese Herbal; Female; Lung Diseases; Microbial Sensitivity Tests; Pseudomonas aeruginosa; Pseudomonas Infections; Rats; Rats, Inbred Lew

Alginate-producing, mucoid P. aeruginosa is frequently found in the lungs of patients with cystic fibrosis (CF), where it causes a chronic infection. The importance of alginate in the pathogenesis was demonstrated by the ability to establish chronic P. aeruginosa lung infection in rats if P. aeruginosa entrapped in minute alginate-beads were inoculated transtracheally. Alginate beads containing P. aeruginosa were formed by nebulizing a suspension of seaweed sodium-alginate and P. aeruginosa into a calcium solution. The alginate bead method of establishing infection was compared to an agar-bead method and proved to be quantitatively similar after 4 weeks. The ability of the two methods to induce formation of precipitins, IgA and IgG antibodies against P. aeruginosa antigens, including outer membrane proteins, flagella, exoenzymes and alginate, was assessed by crossed immunoelectrophoresis, enzyme-linked immunosorbent assay and immunoblotting. The two methods of inducing infection were comparable and infected rats had significantly higher antibody response than rats inoculated with sterile beads. We suggest that the alginate bead model closely resembles the later stages of CF-lung infection and that it offers the theoretical advantage of using a substance which is chemically similar to the alginate produced in vivo by P. aeruginosa.

Topics: Agar; Alginates; Animals; Antigens, Bacterial; Disease Models, Animal; Female; Microspheres; Pneumonia; Pseudomonas aeruginosa; Pseudomonas Infections; Rats; Rats, Inbred Strains

A new agent, 9-chloro-9-(diethylaminophenyl)-10-phenylacridan (C-390), was compared to currently available selective agars for the recovery of Pseudomonas aeruginosa. Media containing C-390 were highly selective for P. aeruginosa and enhanced recovery of the organism from clinical specimens because of the low background level of contaminating microorganisms.

Topics: Acridines; Agar; Bacteria; Culture Media; Digestive System; Feces; Humans; Pseudomonas aeruginosa; Pseudomonas Infections; Sputum

Sterile agar beads plus Pseudomonas aeruginosa injected intratracheally produced local infection in rats, similar to that described for the injection of agar beads containing the same pathogen. It is suggested that it is not necessary for P. aeruginosa to be inside the beads to induce lung infection.

Topics: Adhesiveness; Agar; Animals; Capsules; Lung; Pseudomonas Infections; Rats; Respiratory Tract Infections

A blood isolate of Pseudomonas aeruginosa was encountered which produced, on subculture to Mueller-Hinton agar, markedly adherent, tenacious colonies which were characterized microscopically by the presence of serpentine rows of interlocking bacilli. Factors accounting for the observed morphologic aberration, which was lost upon subculture, remain unknown.

Topics: Agar; Child, Preschool; Female; Humans; Pseudomonas aeruginosa; Pseudomonas Infections; Sepsis; Urinary Tract Infections

Eighty-six clinical isolates of fluorescent pseudomonads that did not produce pyocyanin on Diagnostic Sensitivity Test Agar or Cetrimide Agar were identified on the basis of their antibiotic sensitivity, production of pigment on King's "A" medium, growth at 42 degrees C, production of lecithinase and hydrolysis of gelatin. The identity of the strains was confirmed in tests with the ammonium salt sugars ethanol, glucose and mannitol. These tests were adequate for distinguishing between the three important fluorescent pseudomonads. The detection of casein hydrolysis on milk agar was assessed as a rapid method of distinguishing P. aeruginosa from the other species of fluorescent pseudomonads but proved unhelpful when compared with, or included in, a small set of tests. Most strains of P. aeruginosa and P. fluorescens hydrolysed casein.

Topics: Agar; Caseins; Culture Media; Fluoresceins; Humans; Hydrolysis; Pigments, Biological; Pseudomonas; Pseudomonas aeruginosa; Pseudomonas fluorescens; Pseudomonas Infections

The short-chain acids of 36 strains of Pseudomonas grown on Trypticase soy agar were determined by gas-liquid chromatography. Distinct acid profiles were observed for each of the eight species tested. Propionic, isobutyric, and isovaleric acids were the principal acids detected in media extracts of P. maltophilia, P. cepacia, P. pseudoalcaligenes, P. diminuta, and P. vesiculare. The presence and relative amounts of the isobutyric and isovaleric acids clearly distinguished P. maltophilia, P. pseudoalcaligenes, and P. cepacia from other species. P. diminuta could be distinguished from P. vesiculare by the production of glutaric acid; P. testosteroni was the only species tested which produced relatively large amounts of phenylacetic acid.

Topics: Acetates; Acids; Agar; Bacteriological Techniques; Butyrates; Chromatography, Gas; Glutarates; Glycine max; Humans; Phenylacetates; Propionates; Pseudomonas; Pseudomonas Infections; Species Specificity; Trypsin

Topics: Agar; Carbenicillin; Drug Combinations; Drug Synergism; Framycetin; Gentamicins; Humans; Microbial Sensitivity Tests; Penicillin Resistance; Pseudomonas aeruginosa; Pseudomonas Infections; Seasons; Time Factors

Topics: Agar; Bacteriocins; Bacteriological Techniques; Bacteriuria; Blood; Bone and Bones; Cross Infection; Humans; Mitomycins; Pseudomonas aeruginosa; Pseudomonas Infections; Sputum; Tracheotomy; Ulcer; Wound Infection

Topics: Agar; Bacteriocins; Bacteriological Techniques; Cross Infection; Culture Media; Humans; Mitomycins; Pseudomonas aeruginosa; Pseudomonas Infections

Topics: Agar; Burns; Cross Infection; Drug Resistance; Enterobacteriaceae; Gentamicins; Humans; Pseudomonas aeruginosa; Pseudomonas Infections

A cabinet for detecting the fluorescence of cultures on agar media is described. The use of fluorescence as a criterion for detection of Ps. pyocyanea is compared with that of the oxidase reaction. From a series of patients with burns, all colonies of Gram-negative bacilli which gave a positive oxidase reaction yielded fluorescent subcultures on 0.03% cetrimide agar; all fluorescent cultures on cetrimide agar gave a positive oxidase reaction, but a few mixed cultures which fluoresced on blood agar were not picked for oxidase tests because the colonies of Ps. pyocyanea were overgrown by other bacteria. Out of 1,812 swabs which yielded fluorescent subcultures on 0.03% cetrimide agar, 1,739 (96%) showed strong characteristic fluorescence on the initial blood agar plate culture.

Topics: Agar; Bacteria; Bacteriological Techniques; Culture Media; Gram-Negative Bacteria; Humans; Pseudomonas; Pseudomonas Infections