The effect of clavulanic acid on the susceptibility of Bacteroides fragilis to three acyl-ureidopenicillins, ampicillin and carbenicillin

Publisher Website
Google Scholar
Abstract
The susceptibilities of 50 clinical isolates of the Bacteroides fragilis group to ampicillin, carbenicillin, mezlocillin, azlocillin and piperacillin were similar, modal MICs being 8–32 mg/1. However, in the presence of clavulanic acid, 45 and 43 strains became susceptible (MIC≤4 mg/1) to ampicillin and carbenicillin respectively whilst 27, 37 and 35 strains became susceptible (MIC ≤ 4 mg/1) to mezlocillin, azlocillin and piperacillin. Clavulanic acid did not influence the susceptibility of six (12%) strains. The isoelectric points of the β-lactamases from Bact. fragilis and Bact. thetaio-taomicron were similar to those found by others.