A study on the prevalence of vancomycin resistant and intermediate staphylococcus aureus 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