The effect of minimal inhibitory consantration and subminumum inhibitory consantrations of Vancomycin to virulance in Staphylococcus aureus

The purpose of this study was to observe how vancomycin influences Staphylococcus aureus ATCC 25923?s virulence. Lipases, proteases, hemolysis, slide coagulases, tube coagulases, latex agglutination and biofilm determined as virulance factors. Minimal inhibitory concentration (MIC) of vancomycin against Staphylococcus aureus ATCC 25923 was detected by broth microdilution method. Than production of Stapylococcus aureus lipases, proteases, biofilm, coagulases and latex agglutination tests were checked under sub-MIC and supra-MIC of vancomycin. Lipases were observed on medium with egg-yolk and proteases observed on medium with skim milk. Hemolysis was observed on Colombia agar with %5 sheep blood. Released coagulase was observed by tube coagulase test and attached coagulase was observed by slide coagulase test. Protein A and clumping factor were observed by latex agglutination test. Biofilm production was detected by crystal violet method.Minimal inhibitory concentration (MIC) of vancomycin against Staphylococcus aureus ATCC 25923 was detected 1µg/ml. Slide coagulase were positive under MIC, MIC %50, MIC %25, MIC %12,5 of vancomycin. Latex agglutination were positive under MIC %50, MIC %25, MIC %12,5 of vancomycin. Biofilm were positive under MIC %50, MIC %25, MIC %12,5 of vancomycin. Under MIC %50, MIC %25, MIC %12,5 of vancomycin concentrations tube coagulase became positive at second hour. After 24 hour incubation at 36°C lipase, protease and hemolysis were positive from MIC, MIC %50, MIC %25, MIC %12,5 of vancomycin.Staphylococcus aureus ATCC 25923 conserved production of lipase, protease and hemolysis after exposed to vancomycin. In our study, behaviour and physiopathology of Staphylococcus aureus didn?t change by microenviroment conditions with vancomycin.Key words : Staphylococcus aureus, vancomycin, exoenzymes, surface proteins, biofilm