title: Hyperproduction of TEM-1 beta-lactamase in clinical isolates of Escherichia coli serotype O15.
abstract: During an outbreak of infection with ampicillin-resistant, TEM-1 beta-lactamase-producing Escherichia coli serotype O15, some strains were noted to differ from the majority in that they showed reduced susceptibility to amoxycillin/clavulanic acid (Augmentin), ureidopenicillins and first generation cephalosporins and produced increased amounts of beta-lactamase. The plasmid from one such isolate was compared with that from an isolate that produced normal amounts of beta-lactamase. Restriction analysis with EcoRI revealed extra fragments in the plasmid from the beta-lactamase hyperproducer and use of DNA-DNA hybridisation with a biotinylated TEM-1 probe showed genetic rearrangement in the beta-lactamase hyperproducer so that the TEM gene appeared to be present in larger amounts and was located on a smaller fragment than for the plasmid from the strain that produced normal amounts of beta-lactamase.
authors.affiliation: Department of Microbiology, UMDS, St. Thomas' Campus, London, U.K.
authors.forename: K
authors.initials: K
authors.lastname: Shannon
authors.forename: H
authors.initials: H
authors.lastname: Williams
authors.forename: A
authors.initials: A
authors.lastname: King
authors.forename: I
authors.initials: I
authors.lastname: Phillips
mesh_terms: D004269:DNA, Bacterial / Q000032:analysis; D004352:Drug Resistance, Microbial / Q000235:genetics; D004926:Escherichia coli / Q000145:classification / Q000201:enzymology / Q000235:genetics*; D009693:Nucleic Acid Hybridization; D010957:Plasmids; D012703:Serotyping; D001618:beta-Lactamases / Q000096:biosynthesis / Q000235:genetics*
chemical_list: D004269:DNA, Bacterial; D001618:beta-Lactamases; C034413:beta-lactamase TEM-1