D-Test for Detection of Antimicrobial Susceptibility in Methicillin Resistant Staphylococcus Aureus (MRSA)

Abstract

E-test is a quantitative technique for determining the antimicrobial susceptibility of gram positive and gram negative bacteria. The system comprises a predefined antibiotic gradient which is used to determine the MIC (Minimum Inhibitory Concentration), in µg /ml of different antimicrobial agents against microorganisms as tested on agar media using overnight incubation. MIC of a given antibiotic in µg /ml that will inhibit the growth of a particular bacterium under defined experimental conditions. E-test directly quantifies antimicrobial susceptibility in terms of discrete MIC values. However in using a predefined stable and continuous antibiotic concentration gradient, E-test MIC values can be more precise and reproducible than results obtained from conventional procedures. E-test microbial concentration gradient is preformed, predefined and stable and is not dependent on diffusion. MIC of 0.5 µg /ml, 1 µg /ml and 1.5 µg/ml were observed when Vancomycin E-test was used to determine the glycopeptide susceptibility in MRSA (Methicillin Resistant Staphylococcus aureus).