Effects of Serum and its components on the biofim formation of Pseudomonas aeruginosa / 临床检验杂志

Objective@#To study the effects of serum and its components on biofilm formation of Pseudomonas aeruginosa. @*Methods@#96 well microplates combined with crystal violet staining was used to detect the effects of serum, albumin and transferrin on biofilm formation of Pseudomonas aeruginosa. And confocal laser scanning microscope was used to observe the morphology of the biofilm. @*Results@#The biofilm of PAO1 was significantly enhanced from 2.26±0.42 to 3.42±0.08（t=4.71, p<0.01）with horse serum and but reduced to 0.807±0.10（t=4.71,p<0.01） by human serum; And the total biofilm biomass was significantly increased and clump-changed with horse serum, but decreased and scattered in distribution by human serum. Besides, horse serum could also enhance the biofilm formation of part of the clinical isolates of Pseudomonas aeruginosa, however, human serum could inhibit the biofilm formation of all of the clinical isolates. And 2.5g/L albumin could significantly enhance the biofilm of PAO1 from 1.96±0.22 to 2.54±0.18（t=3.55，p<0.05）, but 5 g/L could reduce the biofilm of PAO1 from 1.85±0.36 to 0.84±0.24（t=4.03，p<0.05）.@*Conclusion@#Horse serum and albumin could significantly promote the biofilm formation of Pseudomonas aeruginosa, but human serum and transferrin could decrease its biofilm formation.

Comparison of germ tube production by candida albicans in various media.

Introduction: Candidiasis is one of the important opportunistic fungal infections in human. Candida albicans (C.albicans) is the predominant Candida species isolated from clinical samples. In routine laboratory, C.albicans is diagnosed on the basis of culture, staining morphology, germ tube production, & chlamydospore formation on cornmeal agar. The objective of this study was to assess the reliability of different media for germ tube production. Material & Methods: The study was carried out on various clinical samples received in Microbiology department of M.P.Shah medical college, Jamnagar from January to July 2011. Among all clinical samples, 100 isolates of C.albicans were compared for germ tube production in 4 different media (sterile horse serum, pooled human serum, trypticase soy broth and Brain heart infusion (BHI) broth. Candida species were also identified by using culture, staining morphology, & chlamydospore formation on cornmeal agar. Results: In our study, among 100 C.albicans isolates, sterile horse serum gave 100% germ tube production, pooled human serum gave 93%, BHI gave 63% and trypticase soy broth gave 60% germ tube production at the end of 2 hours of incubation. Conclusion: This study shows that sterile horse serum is best medium for germ tube production of C.albicans and it can replace human serum which has its disadvantage in being bio hazardous with false negative reporting.

Contribution of serum IL-4 and IgE to the early prediction of horse serum allergies in guinea pigs

BACKGROUND: Horse serum (HS) was a strong allergen for xenogeneic animals. However, the methods of test for allergen didn't authorized in Pharmacopeia of the United States, European Pharmacopeia, Japanese Pharmacopeia and British Pharmacopeia. Thus, new methods of test for allergen are required to control drug allergy. OBJECTIVE: To propose a new method for detecting horse serum induced allergic reactions of guinea pigs earlier. METHODS: Guinea pigs were sensitized successively by injecting different concentration of HS intravenously once a day for three times, serum level of IL-4 and total IgE were detected by method of enzyme linked immunosorbent assay (ELISA) before guinea pigs were challenged by injecting HS intravenously only once, and the results were compared with routine method of sensitization by injecting HS intraperitoneally every other day for three times. RESULTS: Serum level of IL-4 and total IgE increased significantly before guinea pigs were challenged, either in day 8 after intravenous sensitization (10%HS, 0.5 mL) or in day 14 and day 21 after intraperitoneal sensitization (10%HS, 0.5 mL), and allergic reactions occurred in all guinea pigs after challenged by injecting HS (10%, 1.0 mL) only once. CONCLUSION: It provides a new way to predict whether HS or other drugs can provoke allergic reactions earlier by detecting the serum level of IL-4 and total IgE in d8 after intravenous sensitization, this has a good application value in drug emergency test.

Optimization of culture media of pathogenic Mycoplasma hyopneumoniae by a response surface methodology

Composition of culture medium for mass production of Mycoplasma hyopneumoniae was optimized using a response surface methodology (RSM). Initially, the influence of glucose, thallium acetate, fresh yeast extract, horse serum, and porcine serum on the production of mycoplasmal protein was assessed using a 'one factor at a time' technique. Next, factors with a significant effect, including fresh yeast extract, and horse and porcine sera, were selected for further optimization using a central composite design (CCD) of RSM. The experimental results were fitted into a second order polynomial model equation. Estimated optimal condition of the factors for maximum production of mycoplasmal protein (i.e., triple-fold increase from 0.8 mg/L produced by basal mycoplasma media to 2.5 mg/L) was 10.9% fresh yeast extract, 15% horse serum, and 31.5% porcine serum (v/v). For the optimized conditions, a 2.96 mg/L experimental result was observed, similar to the estimated optimal conditions result of the CCD.