RESUMEN
Objective: To determine the frequency of vancomycin resistant Staphylococcus aureus [VRSA] among clinical isolates of methicillin resistant Staphylococcus aureus [MRSA]. Study Design: Descriptive study. Place and Duration of Study: Department of Microbiology, University of Health Sciences, Lahore from Jul 2014 to Dec 2014
Material and Methods: A total of 240 [n=240] clinical isolates of MRSA were collected by consecutive sampling from different tertiary care hospitals of Lahore. Re-confirmation of MRSA was done by the standard microbiological methods using disc diffusion technique according to Clinical Laboratory Standards Institute [CLSI] guidelines 2014. Minimum inhibitory concentration [MIC] of the vancomycin was done by agar dilution method
Results: It was found that vancomycin inhibited MRSA strains in the range of 1.0-2.0 microg/ml. Ninety percent [90%] of the strains inhibited at 1 microg/ml while 25 [10.41%] strains showed growth at 1 microg/ml which indicates that their MIC was 2 microg/ml. No vancomycin resistant [VRSA] or intermediate strains [VISA] of MRSA were found during the study but there were significant numbers of isolates having >/=1 microg/ml MIC of vancomycin
Conclusion: Vancomycin has until now excellent activity against clinical isolates of Methicillin-resistant Staphylococcus aureus