Open AccessDetection of inducible β‐lactamase by an agar dilution technique
Author(s) -
Mulgrave Leigh
Publication year - 1985
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1985.tb01637.x
Subject(s) - cefoxitin , cefotaxime , cefamandole , agar dilution , cephalosporin , microbiology and biotechnology , agar , enterobacter cloacae , chemistry , antimicrobial , enterobacter , chromatography , dilution , biology , antibiotics , enterobacteriaceae , bacteria , escherichia coli , minimum inhibitory concentration , biochemistry , staphylococcus aureus , gene , genetics , physics , thermodynamics
An agar dilution technique for the detection of inducible β‐lactamase‐mediated resistance to the newer cephalosporins is described. Cefoxitin (16 μg/ml) was incorporated in agar plates together with cefamandole (8 μg/ml) or cefotaxime (8 μg/ml). The susceptibility of 35 strains of Enterobacter cloacae to these combinations was compared with their susceptibility to the individual antimicrobial agents. Of 31 strains which could be evaluated, 18 (58%) produced an inducible β‐lactamase which inactivated cefamandole, while 10 (32%) produced an inducible cefotaxime‐inactivating enzyme. The technique has the advantages of being 24 h faster than the alternative disc‐diffusion induction test, and of being suitable for testing large numbers of strains simultaneously.