Evaluation of the Precept microdilution MIC system for single-drug testing in individual trays.

This study presents an evaluation of a commercial system for the MIC testing of single drugs dehydrated in disposable plastic trays (Precept, Austin Biological Laboratories, Inc., Austin, Tex.). The commercial system was compared with a reference agar dilution method, and 203 clinical bacterial isolates were tested by each method. For a total of 767 determinations, there was 94.2% agreement between the two methods, and of the discrepancies encountered, 0.8% were very major, 2.1% were major, and 2.9% were minor. The results suggest that the Precept system may provide a practical and reliable method for MIC determinations of individual antimicrobial agents.