A study on the prevalence of vancomycin resistant and intermediate staphylococcusaureus isolated from various clinical Specimen in a tertiary care hospital and detection of their MIC values by E-test

The main antimicrobial used to treat MRSA infections which are life threatening is a glycopeptide antibiotic, Vancomycin. Inturn extensive use of vancomycin in various parts of the world lead to the a rise in Staphylococcus aureus strains which are resistant to vancomycin.^{(1, 2)} Hence this study was carried out to detect vancomycin resistance in S.aureus isolated from various clinical samples. All 161 Staphylococcus aureus strains were screened for Vancomycin resistance by BHI-Vancomycin screen agar [6μg/ml] and Vancomycin disc diffusion method [30μg/disc]. These were further confirmed by E-test. 82 (51%) strains were MRSA determined by Cefoxitin disc diffusion method and MRSA were maximally isolated from pus (61%). 45% strains were MDR-MRSA. Only 5 S.aureus strains showed resistance to Vancomycin by disc diffusion method, but all these strains were sensitive to Vancomycin by both Vancomycin screen agar [6μg/ml] and E-test, thus this study also showed 100% sensitivity and specificity for BHI-VSA (6μgm/ml). As current study only indicates the tip of iceberg. Hence we suggest, more and more studies should be undertaken in future to monitor the emergence of resistance to these antibiotic.