Klebsiella pneumoniae and other Enterobacteriaceae producing novel plasmid-mediated beta-lactamases markedly active against third-generation cephalosporins: epidemiologic studies.
Analysis of the enzymes produced by clinical isolates of multiresistant Klebsiella pneumoniae from hospitals in France revealed two novel broad-spectrum beta-lactamases. The first, characterized by an isoelectric point of 6.3 and a high hydrolytic activity on cefotaxime, is designated CTX-1. This beta-lactamase was encoded by a 95-kilobase plasmid (incompatibility group 7M) and cotransferred with resistance to tetracyclines, sulfonamides, and aminoglycosides (AAC [6']-IV). From 1984 to June 1987, 490 CTX-1-producing strains of Enterobacteriaceae were isolated. The second plasmid-mediated beta-lactamase (CAZ-1) was isolated in 1987 from three K. pneumoniae strains more resistant to ceftazidime than to other third-generation cephalosporins. This broad-spectrum beta-lactamase differed from CTX-1 by its isoelectric point--close to 5.6--and its high hydrolytic activity on ceftazidime and was encoded by a 150-kilobase plasmid. It was demonstrated that these expanded-spectrum beta-lactamases are TEM derivatives.
Sirot
J
J
Service de Bactériologie Virologie, Faculté de Médecine, Clermont-Ferrand, France.
Chanal
C
C
Petit
A
A
Sirot
D
D
Labia
R
R
Gerbaud
G
G
D002511:Cephalosporins / Q000378:metabolism / Q000494:pharmacology*; D004196:Disease Outbreaks; D004352:Drug Resistance, Microbial; D004755:Enterobacteriaceae / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D004756:Enterobacteriaceae Infections / Q000453:epidemiology* / Q000382:microbiology; D006801:Humans; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D010957:Plasmids; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000235:genetics
D002511:Cephalosporins; D001618:beta-Lactamases