Quality control limits for microdilution susceptibility tests with aztreonam, imipenem, ceftriaxone, ceftazidime,...

A six-laboratory collaborative study was performed in order to define quality control limits for microdilution tests with seven new beta-lactams (aztreonam, imipenem, ceftriaxone, ceftazidime, ceftizoxime, cefuroxime, and cefonicid). Four standard control strains were tested and the expected MIC limits for each of the appropriate drug-microorganism combinations were defined.