title: The role of beta-lactamase and the permeability barrier on the activity of cephalosporins against members of the Bacteroides fragilis group.
abstract: The role of beta-lactamase and the permeability barrier on the activity of some beta-lactams against 53 strains of the Bacteroides fragilis group was investigated. Minimal inhibitory concentrations of cefamandole, cefoxitin, and cephalothin were determined with or without the addition of clavulanic acid and (or) ethylenediaminetetraacetate using an agar dilution technique. A significant increase of susceptibility with clavulanic acid indicated a role for beta-lactamase, and with ethylenediaminetetraacetate, a role for a permeability barrier. We found that both beta-lactamase and low permeability decreased the activity of the beta-lactams to some extent depending on the bacterial species and the antibiotic. The species-specific exception was B. distasonis which showed only a permeability barrier to all antibiotics tested.
mesh_terms: D001439:Bacteroides / Q000187:drug effects* / Q000378:metabolism; D001441:Bacteroides fragilis / Q000187:drug effects* / Q000378:metabolism; D002435:Cefamandole / Q000378:metabolism / Q000494:pharmacology; D002440:Cefoxitin / Q000378:metabolism / Q000494:pharmacology; D002463:Cell Membrane Permeability; D002511:Cephalosporins / Q000378:metabolism / Q000494:pharmacology*; D002512:Cephalothin / Q000378:metabolism / Q000494:pharmacology; D019818:Clavulanic Acid; D002969:Clavulanic Acids / Q000494:pharmacology; D004352:Drug Resistance, Microbial; D004492:Edetic Acid / Q000494:pharmacology; D013045:Species Specificity; D001618:beta-Lactamases / Q000378:metabolism*
chemical_list: D002511:Cephalosporins; D002969:Clavulanic Acids; D019818:Clavulanic Acid; D002435:Cefamandole; D002440:Cefoxitin; D004492:Edetic Acid; D001618:beta-Lactamases; D002512:Cephalothin