Chapter 7.9 : Susceptibility Testing by TREK Sensititre Microdilution Plates

Abstract:

Antimicrobial susceptibility testing is performed on rapidly growing mycobacteria isolated from clinical specimens by using a broth microdilution method (for research use only) with TREK Sensititre 96-well plate for Rapid Growing Mycobacteria (RGM) (RAPMYCO; Thermo Scientific, Cleveland, OH). These include Mycobacterium fortuitum group (M. fortuitum, Mycobacterium peregrinum, and the species included in the former M. fortuitum third biovariant complex), Mycobacterium chelonae, Mycobacterium abscessus, Mycobacterium massiliense, Mycobacterium bolletii, Mycobacterium mucogenicum, and Mycobacterium smegmatis group (M. smegmatis, Mycobacterium goodii, Mycobacterium wolinskyi). Microtiter plates are dosed with antimicrobial agents at appropriate concentrations and the results are read by visual observation of growth in each well. The final result is recorded as MIC, which is the lowest concentration of an antimicrobial agent that prevents visible growth of the microorganism tested. The MIC value is then used to determine if the microorganism is susceptible, exhibits intermediate or full resistance to the drug of interest.