title: OXA-163, an OXA-48-related class D β-lactamase with extended activity toward expanded-spectrum cephalosporins.
abstract: Two bla(OXA-48)-like-positive isolates (Klebsiella pneumoniae and Enterobacter cloacae) were recovered in Argentina in 2008 as part of a large-scale survey focused on multidrug resistance in Enterobacteriaceae. In both cases, sequencing identified β-lactamase OXA-163, differing from OXA-48 by a single amino substitution and a 4-amino-acid deletion. OXA-163 hydrolyzed penicillins, ceftazidime, and cefotaxime, whereas OXA-48 did not. However, OXA-163 had a much lower ability to hydrolyze carbapenems than OXA-48, therefore barely being considered a carbapenemase. In both isolates, the bla(OXA-163) gene was located on plasmids that differed in structure and size. However, a detailed genetic analysis revealed a similar genetic context in those isolates, with the bla(OXA-163) gene being bracketed by novel transposase genes, making this genetic environment different from that reported for the bla(OXA-48) gene. This study identified the first class D β-lactamase compromising both extended-spectrum cephalosporin and carbapenem activities.
authors.affiliation: Service de Bactériologie-Virologie, Hôpital de Bicêtre, 78 rue du General Leclerc, Le Kremlin Bicêtre 94275, France. laurent.poirel@bct.aphp.fr
authors.forename: Laurent
authors.initials: L
authors.lastname: Poirel
authors.forename: Mariana
authors.initials: M
authors.lastname: Castanheira
authors.forename: Amélie
authors.initials: A
authors.lastname: Carrër
authors.forename: Carla Parada
authors.initials: CP
authors.lastname: Rodriguez
authors.forename: Ronald N
authors.initials: RN
authors.lastname: Jones
authors.forename: Jorgelina
authors.initials: J
authors.lastname: Smayevsky
authors.forename: Patrice
authors.initials: P
authors.lastname: Nordmann
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000378:metabolism*; D002511:Cephalosporins / Q000378:metabolism*; D016972:Enterobacter cloacae / Q000201:enzymology; D006801:Humans; D007711:Klebsiella pneumoniae / Q000201:enzymology; D008969:Molecular Sequence Data; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D001618:beta-Lactamases; C108449:oxacillinase