Open AccessSodium Clavulanate Potentiation of Cephalosporin Activity Against Clinical Isolates of Cephalothin-Resistant Klebsiella pneumoniae
Author(s) -
Roger T. Jackson,
LeRoy F. Harris,
Robert H. Alford
Publication year - 1978
Publication title -
antimicrobial agents and chemotherapy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.07
H-Index - 259
eISSN - 1070-6283
pISSN - 0066-4804
DOI - 10.1128/aac.14.1.118
Subject(s) - agar dilution , cefoxitin , klebsiella pneumoniae , cephalosporin , microbiology and biotechnology , klebsiella , clavulanic acid , biology , agar , minimum inhibitory concentration , bacteria , antibiotics , escherichia coli , amoxicillin , staphylococcus aureus , biochemistry , genetics , gene
Plasmid-carryingKlebsiella pneunomiae clinical isolates with agar dilution minimum inhibitory concentrations (MIC) of 32 μg/ml or greater were tested for in vitro potentiation of cephalothin activity by clavulanic acid (BRL-14151), an inhibitor of beta-lactamases. The addition of 10 μg of clavulanate per ml caused greater than a 500-fold reduction in geometric mean cephalothin agar dilution MIC, with lesser but significant reductions resulting from clavulanate concentrations of 5 or 1 μg/ml. Clavulanate-potentiated reduction of cephalothin MICs in broth against resistantKlebsiella were comparable to reduction in agar dilution MICs as a rule. However, a low concentration (1 μg/ml) of clavulanate produced cephalothin MICs in broth several-fold higher than by the agar dilution method. Modest cephalothin-potentiating effects of clavulanate on cephalothin-susceptible strains and on cefoxitin against cephalothin-resistantKlebsiella strongly suggested that the major effect of clavulanate was beta-lactamase inhibition.