Chapter 5.7 : Broth Microdilution MIC Test for Anaerobic Bacteria

Abstract:

The broth microdilution MIC method can be used to measure (semiquantitatively) the in vitro activity of an antimicrobial agent against an anaerobic bacterial isolate. This procedure is very similar to the broth microdilution method used for aerobic bacteria. Various concentrations of antimicrobial agents are dispensed into a multiwell plastic tray and inoculated with a test isolate. After 48 h of incubation at 35°C in an anaerobic environment, the MIC is determined by observing the lowest concentration of an antimicrobial agent which will inhibit visible growth of the test bacterium. MICs obtained are interpreted as susceptible, intermediate, or resistant, based on criteria defined by the NCCLS ( 1 ).