Evaluation of disk approximation and agar dilution induction tests for demonstration of in vitro antagonism of cefotaxime by cefoxitin in Enterobacter species.
Cefoxitin-resistant clinical isolates of Enterobacter spp. demonstrated inducible beta-lactamase activity in 31 of 47 (65.9%) disk approximation tests and in 32 of 52 (63.5%) agar dilution induction tests. Agreement between the two results was only 72.3%, and 80.9% of the strains were positive in at least one induction test. Lack of valid interpretive criteria preclude their routine use in the clinical laboratory.
D002439:Cefotaxime / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D002440:Cefoxitin / Q000494:pharmacology*; D004352:Drug Resistance, Microbial; D004754:Enterobacter / Q000187:drug effects* / Q000201:enzymology; D004755:Enterobacteriaceae / Q000187:drug effects*; D004790:Enzyme Induction; D006801:Humans; D008826:Microbial Sensitivity Tests; D011237:Predictive Value of Tests; D001618:beta-Lactamases / Q000096:biosynthesis*
D002440:Cefoxitin; D001618:beta-Lactamases; D002439:Cefotaxime