title: Characterization of a novel extended-spectrum β-lactamase phenotype from OXA-1 expression in Salmonella Typhimurium strains from Africa and Ireland.
abstract: Salmonella enterica (S. Typhimurium) strains from Kenya, Malawi, and Ireland showing elevated cefepime MIC values carried bla(OXA-1). These strains were not detected by current guidelines for extended-spectrum β-lactamase production based on MIC values or clavulanate inhibition, since cefepime is a preferred substrate for OXA-1 and this enzyme is reported to be resistant to clavulanate inhibition. bla(OXA-1) was located within a class I integron and an activated P(2) promoter was identified upstream of bla(OXA-1). P(2) was activated by the insertion of a triplet 'GGG' upstream of the -10 signal. All African strains were ST313, prevalent in this continent, and the Irish isolate belonged to ST19.
authors.affiliation: School of Medicine, National University of Ireland, Galway, Ireland. fiona.boyle@nuigalway.ie
authors.forename: Fiona
authors.initials: F
authors.lastname: Boyle
authors.forename: Gerard
authors.initials: G
authors.lastname: Healy
authors.forename: James
authors.initials: J
authors.lastname: Hale
authors.forename: Samuel
authors.initials: S
authors.lastname: Kariuki
authors.forename: Martin
authors.initials: M
authors.lastname: Cormican
authors.forename: Dearbháile
authors.initials: D
authors.lastname: Morris
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004269:DNA, Bacterial / Q000235:genetics; D006801:Humans; D007494:Ireland; D007630:Kenya; D008295:Malawi; D008826:Microbial Sensitivity Tests / Q000379:methods; D016254:Mutagenesis, Insertional; D011401:Promoter Regions, Genetic; D012486:Salmonella typhimurium / Q000187:drug effects* / Q000201:enzymology* / Q000302:isolation & purification; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*; D047090:beta-Lactams / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D047090:beta-Lactams; C039404:beta-lactamase OXA-2; D001618:beta-Lactamases