title: Emergence of plasmid-mediated quinolone resistance in Escherichia coli in Europe.
abstract: Although quinolone resistance results mostly from chromosomal mutations, it may also be mediated by a plasmid-encoded qnr gene in members of the family Enterobacteriaceae. Thus, 297 nalidixic-acid resistant strains of 2,700 Escherichia coli strains that had been isolated at the Bicetre Hospital (Le Kremlin-Bicetre, France) in 2003 were screened for qnr by PCR. A single E. coli isolate that carried a ca. 180-kb conjugative plasmid encoding a qnr determinant was identified. It conferred low-level resistance to quinolones and was associated with a chromosomal mutation in subunit A of the topoisomerase II gene. The qnr gene was located on a sul1-type class 1 integron just downstream of a conserved region (CR) element (CR1) comprising the Orf513 recombinase. Promoter sequences for qnr expression overlapped the extremity of CR1, indicating the role of CR1 in the expression of antibiotic resistance genes. This integron was different from other qnr-positive sul1-type integrons identified in American and Chinese enterobacterial isolates. In addition, plasmid pQR1 carried another class 1 integron that was identical to In53 from E. coli. The latter integron possessed a series of gene cassettes, including those coding for the extended-spectrum beta-lactamase VEB-1, the rifampin ADP ribosyltransferase ARR-2, and several aminoglycoside resistance markers. This is the first report of plasmid-mediated quinolone resistance in Europe associated with an unknown level of plasmid-mediated multidrug resistance in Enterobacteriaceae.
authors.affiliation: Service de Bactériologie-Virologie, Hôpital de Bicêtre, 78 rue du Général Leclerc, 94275 Le Kremlin-Bicêtre cedex, France.
authors.forename: Hedi
authors.initials: H
authors.lastname: Mammeri
authors.forename: Marc
authors.initials: M
authors.lastname: Van De Loo
authors.forename: Laurent
authors.initials: L
authors.lastname: Poirel
authors.forename: Luis
authors.initials: L
authors.lastname: Martinez-Martinez
authors.forename: Patrice
authors.initials: P
authors.lastname: Nordmann
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D001483:Base Sequence; D003227:Conjugation, Genetic; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics; D004927:Escherichia coli Infections / Q000382:microbiology; D029968:Escherichia coli Proteins / Q000235:genetics*; D005060:Europe; D006801:Humans; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D009268:Nalidixic Acid / Q000494:pharmacology; D010957:Plasmids / Q000235:genetics*; D016133:Polymerase Chain Reaction; D015363:Quinolones / Q000494:pharmacology*; D017422:Sequence Analysis, DNA
chemical_list: D000890:Anti-Infective Agents; D029968:Escherichia coli Proteins; C485384:Qnr protein, E coli; D015363:Quinolones; D009268:Nalidixic Acid