Determination of Vancomycin MIC In Staphylococcus aureus for Isolates Showing Reduced Zone of Inhibition By Disc Diffusion Method

T.N.Ravi; V.Praveen Kumar; B.V.Ramana

Volume : VIII, Issue : VII, July - 2018

Determination of Vancomycin MIC In Staphylococcus aureus for Isolates Showing Reduced Zone of Inhibition By Disc Diffusion Method

T. N. Ravi, V. Praveen Kumar, B. V. Ramana

Abstract :

Introduction: Methicillin Resistant Staphylococcus aureus (MRSA) is resistant to the majority of antimicrobial agents available for clinical use, the glycopeptidesvancomycin has been proposed as the drug of choice for treating such infections.Indiscriminate use of vancomycin leads to the emergence and spread of vancomycin resistance in multidrug resistant strains is of growing concern in the recent years.The minimum inhibitory concentration (MIC) represents the concentration of antimicrobial at which there is complete inhibition of growth of organism. Measurement of minimum inhibitory concentration (MIC) of antibiotics is an important aid to determine antibiotic resistance to the bacteria.Materials and Methods: The present study aims to determine the MIC of 240Staphylococcus aureus which showed reduced zone of inhibition by Vancomycin disk diffusion test. Minimal inhibitory concentration (MIC) of vancomycin was determined by agar dilution method in Muller Hinton agarResults:Out of 240 S.aureus 225 isolates were VSSA (MIC≤ 2 µg/mL ), 12 were VISA (MIC 4–8 µg/mL) and 3 strains were VRSA (MIC>16 µg /mL ). Conclusion: Wide spread usage of vancomycin to treat infections caused by MRSA has been reported to result in the emergence of low level resistance. Continuous efforts should be made to prevent the spread and the emergence of glycopeptide resistance by early detection of the resistant strains and using the proper infection control measures in the hospital setting.