title: Synergistic effects of dicloxacillin or clavulanic acid in combination with penicillin G or cephalothin against Yersinia enterocolitica.
abstract: Cultures of Yersinia enterocolitica grown at 22 degrees C produced beta-lactamases, whereas cultures grown at 37 degrees C produced these enzymes much less effectively. Both dicloxacillin and clavulanic acid inhibited the beta-lactamase activity of bacterial crude extracts and potentiated the activity of penicillin G or cephalothin against 14 Y. enterocolitica strains. It appeared that the beta-lactamase activity present in Y. enterocolitica cells grown at 37 degrees C was great enough to play a role in bacterial resistance to beta-lactam antibiotics, since combining penicillin G or cephalothin with clavulanic acid or dicloxacillin resulted in synergistic activity against cultures grown at 37 degrees C that was equal to or greater than the activity against cultures grown at 22 degrees C.
mesh_terms: D002511:Cephalosporins / Q000494:pharmacology; D002512:Cephalothin / Q000494:pharmacology*; D019818:Clavulanic Acid; D002969:Clavulanic Acids / Q000494:pharmacology*; D004009:Dicloxacillin / Q000494:pharmacology*; D004357:Drug Synergism; D008826:Microbial Sensitivity Tests; D010400:Penicillin G / Q000494:pharmacology*; D015008:Yersinia enterocolitica / Q000187:drug effects*; D065093:beta-Lactamase Inhibitors
chemical_list: D002511:Cephalosporins; D002969:Clavulanic Acids; D065093:beta-Lactamase Inhibitors; D019818:Clavulanic Acid; D004009:Dicloxacillin; C021720:nitrocefin; D010400:Penicillin G; D002512:Cephalothin