title: Genetic and functional variability of AmpC-type β-lactamases from Acinetobacter baumannii.
abstract: The incidence of naturally occurring AmpC β-lactamases with extended activities toward several cephalosporins was evaluated among 17 ceftazidime (CAZ)-resistant Acinetobacter baumannii isolates. Five AmpC β-lactamases (named ADC β-lactamases) were identified, among which those possessing the Val208Ala (inside the omega-loop) or Asn283Ser (helix H-10) substitution conferred higher levels of resistance (4- to 64-fold higher) to CAZ and to cefotaxime in Escherichia coli. This study demonstrates that peculiar AmpCs playing a role in resistance to broad-spectrum cephalosporins in A. baumannii may be identified.
authors: Service de Bactériologie-Virologie, INSERM U914 Emerging Resistance to Antibiotics, Assistance Publique/Hôpitaux de Paris, Hôpital de Bicêtre, 78 Rue du Général Leclerc, Le Kremlin-Bicêtre Cedex, France.
authors: José-Manuel
authors: JM
authors: Rodríguez-Martínez
authors: Laurent
authors: L
authors: Poirel
authors: Patrice
authors: P
authors: Nordmann
mesh_terms: D040981:Acinetobacter baumannii / Q000201:enzymology*; D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002439:Cefotaxime / Q000494:pharmacology; D002442:Ceftazidime / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D001618:beta-Lactamases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D002442:Ceftazidime; C048795:AmpC beta-lactamases; D001618:beta-Lactamases; D002439:Cefotaxime