title: Genetic and biochemical characterization of OXA-405, an OXA-48-type extended-spectrum β-lactamase without significant carbapenemase activity.
abstract: The epidemiology of carbapenemases worldwide is showing that OXA-48 variants are becoming the predominant carbapenemase type in Enterobacteriaceae in many countries. However, not all OXA-48 variants possess significant activity toward carbapenems (e.g., OXA-163). Two Serratia marcescens isolates with resistance either to carbapenems or to extended-spectrum cephalosporins were successively recovered from the same patient. A genomic comparison using pulsed-field gel electrophoresis and automated Rep-PCR typing identified a 97.8% similarity between the two isolates. Both strains were resistant to penicillins and first-generation cephalosporins. The first isolate was susceptible to expanded-spectrum cephalosporins, was resistant to carbapenems, and had a significant carbapenemase activity (positive Carba NP test) related to the expression of OXA-48. The second isolate was resistant to expanded-spectrum cephalosporins, was susceptible to carbapenems, and did not express a significant imipenemase activity, (negative for the Carba NP test) despite possessing a blaOXA-48-type gene. Sequencing identified a novel OXA-48-type β-lactamase, OXA-405, with a four-amino-acid deletion compared to OXA-48. The blaOXA-405 gene was located on a ca. 46-kb plasmid identical to the prototype IncL/M blaOXA-48-carrying plasmid except for a ca. 16.4-kb deletion in the tra operon, leading to the suppression of self-conjugation properties. Biochemical analysis showed that OXA-405 has clavulanic acid-inhibited activity toward expanded-spectrum activity without significant imipenemase activity. This is the first identification of a successive switch of catalytic activity in OXA-48-like β-lactamases, suggesting their plasticity. Therefore, this report suggests that the first-line screening of carbapenemase producers in Enterobacteriaceae may be based on the biochemical detection of carbapenemase activity in clinical settings.
authors: INSERM U 914, Le Kremlin-Bicêtre, France Associated National Reference Center for Antibiotic Resistance, Le Kremlin-Bicêtre, France Faculty of Medicine, South-Paris University, Le Kremlin-Bicêtre, France Bacteriology-Hygiene Unit, Bicêtre Hospital, Assistance Publique/Hôpitaux de Paris, Le Kremlin-Bicêtre, France.
authors: Laurent
authors: http://orcid.org/0000-0001-6596-7384
authors: L
authors: Dortet
authors: INSERM U 914, Le Kremlin-Bicêtre, France.
authors: Saoussen
authors: S
authors: Oueslati
authors: Associated National Reference Center for Antibiotic Resistance, Le Kremlin-Bicêtre, France Besançon Hospital, Microbiology Laboratory, Besançon, France.
authors: Katy
authors: K
authors: Jeannot
authors: Brest Hospital, Microbiology Laboratory, Brest, France.
authors: Didier
authors: D
authors: Tandé
authors: INSERM U 914, Le Kremlin-Bicêtre, France Associated National Reference Center for Antibiotic Resistance, Le Kremlin-Bicêtre, France Faculty of Medicine, South-Paris University, Le Kremlin-Bicêtre, France Bacteriology-Hygiene Unit, Bicêtre Hospital, Assistance Publique/Hôpitaux de Paris, Le Kremlin-Bicêtre, France.
authors: Thierry
authors: T
authors: Naas
authors: INSERM U 914, Le Kremlin-Bicêtre, France Associated National Reference Center for Antibiotic Resistance, Le Kremlin-Bicêtre, France Medical and Microbiology Unit, Department of Medicine, University Fribourg, Fribourg, Switzerland HFR-Hôpital Cantonal, Fribourg, Switzerland patrice.nordmann@unifr.ch.
authors: Patrice
authors: P
authors: Nordmann
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D015780:Carbapenems / Q000627:therapeutic use; D002511:Cephalosporins / Q000627:therapeutic use; D004269:DNA, Bacterial / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D005260:Female; D006801:Humans; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics; D017422:Sequence Analysis, DNA; D016868:Serratia Infections / Q000188:drug therapy* / Q000382:microbiology; D012706:Serratia marcescens / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D001618:beta-Lactamases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D015780:Carbapenems; D002511:Cephalosporins; D004269:DNA, Bacterial; D001618:beta-Lactamases; C000606254:beta-lactamase OXA-405, Serratia marcescens; C063912:carbapenemase