Serial dilution antibiotic susceptibility testing evaluation of a micromethod for use in a diagnostic laboratory

Simultaneous MIC determinations were performed by the conventional tube dilution method and a microdilution technique. Forty-five clinical isolates and 11 antibiotics were used. Results of the two tests revealed 89.2% aggrement of +/- one dilution. The microdilution method was found to be reliable, reproducible and economical in time, labour and materials. The use of pH indicator in the microtechnique is recommended for certain organisms.