TEM-4, a new plasmid-mediated beta-lactamase that hydrolyzes broad-spectrum cephalosporins in a clinical isolate of Escherichia coli.
A clinical isolate of Escherichia coli, strain CB-134, recovered in 1986 from an abdominal abscess, exhibited resistance to penams, oxyimino-beta-lactams including broad-spectrum cephalosporins (cefotaxime, ceftriaxone, ceftazidime), and aztreonam but remained susceptible to cephamycins (cefoxitin, cefotetan) and to moxalactam and imipenem. Clavulanate (2 micrograms/ml) restored the susceptibility of the strain to broad-spectrum cephalosporins and aztreonam. A beta-lactamase with an isoelectric point (pI) of 5.9 was detected in strain CB-134, and the corresponding gene was transferred by conjugation to E. coli together with the associated aminoglycoside resistance determinant [AAC(3)-II] and tetracycline, trimethoprim, and sulfonamide resistance. The beta-lactamase efficiently hydrolyzed cefotaxime and ceftriaxone but only moderately hydrolyzed ceftazidime and was inhibited by clavulanate and sulbactam (1 microM) and by anti-TEM-1 and anti-TEM-2 sera. This extended-spectrum beta-lactamase, conferring resistance to cefotaxime, ceftriaxone, ceftazidime, and aztreonam, was comparable to CTX-1 (TEM-3) but differed from it by pI. Agarose gel electrophoresis of the plasmid DNA indicated that this new enzyme was coded by pUD16, a plasmid of 220 kilobases which belongs to the Inc6 incompatibility group. Hybridization with an intragenic probe for TEM-1 revealed that this beta-lactamase derives from TEM-type beta-lactamases and hence it was named TEM-4.
Paul
G C
GC
Laboratoire de Bactériologie, Faculté de Médecine Cochin-Port-Royal, Paris, France.
Gerbaud
G
G
Bure
A
A
Philippon
A M
AM
Pangon
B
B
Courvalin
P
P
D002511:Cephalosporins / Q000378:metabolism*; D002969:Clavulanic Acids / Q000494:pharmacology; D003227:Conjugation, Genetic; D004269:DNA, Bacterial / Q000235:genetics; D004352:Drug Resistance, Microbial / Q000235:genetics*; D004587:Electrophoresis, Agar Gel; D004926:Escherichia coli / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D006868:Hydrolysis; D007525:Isoelectric Focusing; D007700:Kinetics; D008826:Microbial Sensitivity Tests; D008970:Molecular Weight; D009693:Nucleic Acid Hybridization; D010957:Plasmids; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*
D002511:Cephalosporins; D002969:Clavulanic Acids; D004269:DNA, Bacterial; D001618:beta-Lactamases