The effect of clavulanic acid on the susceptibility of Bacteroides fragilis to three acyl-ureidopenicillins, ampicillin and carbenicillin.
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/l. However, in the presence of clavulanic acid, 45 and 43 strains became susceptible (MIC less than or equal to 4 mg/l) to ampicillin and carbenicillin respectively whilst 27, 37 and 35 strains became susceptible (MIC less than or equal to 4 mg/l) to mezlocillin, azlocillin and piperacillin. Clavulanic acid did not influence the susceptibility of six (12%) strains. The isoelectric points of the beta-lactamases from Bact. fragilis and Bact. thetaiotaomicron were similar to those found by others.
D000667:Ampicillin / Q000494:pharmacology*; D001390:Azlocillin / Q000494:pharmacology*; D001441:Bacteroides fragilis / Q000187:drug effects* / Q000201:enzymology; D002228:Carbenicillin / Q000494:pharmacology*; D019818:Clavulanic Acid; D002969:Clavulanic Acids / Q000494:pharmacology*; D007525:Isoelectric Focusing; D008802:Mezlocillin / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D010878:Piperacillin / Q000494:pharmacology*; D001618:beta-Lactamases / Q000302:isolation & purification / Q000378:metabolism
D002969:Clavulanic Acids; D019818:Clavulanic Acid; D000667:Ampicillin; D001618:beta-Lactamases; D002228:Carbenicillin; D001390:Azlocillin; D008802:Mezlocillin; D010878:Piperacillin