ANTIBIOTIC SUSCEPTIBILITY TESTING: A REVIEW ON CURRENT PRACTICES

Uddhav S Bagul*and Sivagurunathan M. Sivakumar

An increasing Antimicrobial resistance (AMR) has resulted in morbidity and mortality from treatment failures and increased health care costs. Appropriate antimicrobial drug use has unquestionable benefit, but physicians and the public frequently use these agents inappropriately hence, it became necessary to perform the antimicrobial susceptibility test as a routine. The aim of antimicrobial susceptibility testing is to determine the lowest concentration of existing or even new antimicrobial agents which inhibits the visible growth of the bacterium being investigated, under certain test conditions. The Disk diffusion, well diffusion, stokes and gradient diffusion methods are manual methods that provide flexibility and possible cost savings. The most commonly used testing methods include broth microdilution method using commercially available 96-well micro dilution panel. Broth dilution, tube dilution and E test provide quantitative results (e.g. Minimal Inhibitory Concentration) whereas other methods provide qualitative results which are categorized as susceptible, intermediate or resistant. Although available testing methods provide accurate detection of common antimicrobial resistance mechanisms, emerging newer mechanisms of resistance certainly attracts researcher for the development of advanced, reproducible, automated and reliable antimicrobial testing methods.