title: Tentative interpretive criteria for in vitro antibacterial susceptibility testing with imipenem.
abstract: Imipenem is a member of a new class of highly potent beta-lactam antibiotics, carbapenems, with a very broad antibacterial spectrum. This study was undertaken to determine tentative interpretive criteria for in vitro susceptibility testing with 10-micrograms imipenem disks. A careful examination of the zone diameters and the corresponding MICs for 489 clinical isolates by regression-line analysis and the error rate-bounded classification scheme suggested the following guidelines: greater than or equal to 16 mm with an MIC correlate of less than or equal to 4 micrograms/ml for susceptible, 14 to 15 mm (8 micrograms/ml) for moderately susceptible, and less than or equal to 13 mm (greater than or equal to 16 micrograms/ml) for resistant. Lack of cross-resistance between imipenem and broad-spectrum cephalosporins such as cefotaxime and ceftazidime argues against their use as class disks to predict in vitro susceptibility of bacterial species to carbapenems.
mesh_terms: D001419:Bacteria / Q000187:drug effects*; D002439:Cefotaxime / Q000494:pharmacology; D002442:Ceftazidime / Q000494:pharmacology; D015377:Cilastatin; D003521:Cyclopropanes / Q000494:pharmacology; D004352:Drug Resistance, Microbial; D004755:Enterobacteriaceae / Q000187:drug effects; D015378:Imipenem; D008826:Microbial Sensitivity Tests; D011549:Pseudomonas / Q000187:drug effects; D013210:Staphylococcus / Q000187:drug effects; D013845:Thienamycins / Q000494:pharmacology*
chemical_list: D003521:Cyclopropanes; D013845:Thienamycins; D015377:Cilastatin; D015378:Imipenem; D002442:Ceftazidime; D002439:Cefotaxime