Novel plasmid-mediated beta-lactamase from Escherichia coli that inactivates oxyimino-cephalosporins.
A highly cephem-resistant Escherichia coli strain, FP1546, isolated from the fecal flora of laboratory dogs previously administered beta-lactam antibiotics was found to produce a beta-lactamase, FEC-1, of 48-kilodalton size and pI 8.2. FEC-1 hydrolyzed cefuroxime, cefotaxime, cefmenoxime, and ceftriaxone, as well as the enzymatically less-stable antibiotics cephaloridine, cefotiam, and cefpiramide. Of the oxyimino-cephalosporins, ceftizoxime was fairly stable to FEC-1. FEC-1 differed notably from chromosomal E. coli cephalosporinase, especially in its broad-spectrum substrate profile and its high inhibition by clavulanic acid, sulbactam, and imipenem. A conjugation study revealed that FEC-1 was encoded by a 74-megadalton plasmid, pFCX1. This may be the first instance of a plasmid-mediated oxyimino-cephalosporinase from E. coli.
Matsumoto
Y
Y
Research Laboratories, Fujisawa Pharmaceutical Co., Ltd., Osaka, Japan.
Ikeda
F
F
Kamimura
T
T
Yokota
Y
Y
Mine
Y
Y
D000818:Animals; D002511:Cephalosporins / Q000378:metabolism* / Q000494:pharmacology; D003227:Conjugation, Genetic; D004269:DNA, Bacterial / Q000032:analysis; D004285:Dogs; D004352:Drug Resistance, Microbial; D004587:Electrophoresis, Agar Gel; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D006868:Hydrolysis; D007700:Kinetics; D011815:R Factors; D013379:Substrate Specificity; D065093:beta-Lactamase Inhibitors; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*
D002511:Cephalosporins; D004269:DNA, Bacterial; D065093:beta-Lactamase Inhibitors; D001618:beta-Lactamases