title: Prevalence of quinolone resistance determinant qnrA6 among broad- and extended-spectrum beta-lactam-resistant Proteus mirabilis and Morganella morganii clinical isolates with sul1-type class 1 integron association in a Tunisian Hospital.
abstract: OBJECTIVE
  The aim of this study was to investigate the prevalence and the emergence of plasmid-mediated quinolone resistance among broad-spectrum beta-lactam-resistant Proteus mirabilis and Morganella morganii clinical isolates recovered in the Military Hospital in Tunisia.
  
  
  METHODS
  Of 200 strains examined, 50 exhibited resistance to quinolones. Quinolone resistance determinants (qnr and aac(6')-Ib-cr) were characterized by multiplex PCR and sequencing. Chromosomal quinolone resistance mutations in the quinolone resistance-determining region (QRDR) and class 1 integron characterization were analysed by PCR and sequencing. The clonal relationship between the isolates was studied by pulsed-field gel electrophoresis (PFGE).
  
  
  RESULTS
  Fourteen isolates harboured qnrA6 and among them 8 (57%) were extended-spectrum beta-lactamase (ESBL) producers, whilst 12 (85%) isolates harboured blaDHA-1. Mutations in the QRDR were detected in gyrA (Ser83Ile, Glu87Lys), gyrB (Ser464Phe), and parC (Ser80Ile). qnrA6 and blaDHA-1 genes were found embedded in complex sul1-type class 1 integrons. A gene cassette carrying aac(6')-Ib-cr was found located in the class 1 integron upstream of the qacEΔ1 gene. According to the PFGE analysis, the isolates were clonally unrelated.
  
  
  CONCLUSIONS
  This is the first description in North Africa of class 1 integrons carrying blaDHA-1, qnrA6 gene, and aac(6')-Ib-cr determinants in clinical strains of Proteus mirabilis and Morganella morganii.
authors.affiliation: Laboratory of Biochemistry and Biotechnology, Department of Biology, Faculty of Sciences of Tunis, Tunis, Tunisia. sihemmahrouki@yahoo.fr
authors.forename: Sihem
authors.initials: S
authors.lastname: Mahrouki
authors.forename: Mariagrazia
authors.initials: M
authors.lastname: Perilli
authors.forename: Amel
authors.initials: A
authors.lastname: Bourouis
authors.forename: Hela
authors.initials: H
authors.lastname: Chihi
authors.forename: Mustapha
authors.initials: M
authors.lastname: Ferjani
authors.forename: Mohamed
authors.initials: M
authors.lastname: Ben Moussa
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Amicosante
authors.forename: Omrane
authors.initials: O
authors.lastname: Belhadj
mesh_terms: D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004269:DNA, Bacterial / Q000235:genetics; D024881:Drug Resistance, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D004756:Enterobacteriaceae Infections / Q000382:microbiology*; D005260:Female; D005798:Genes, Bacterial; D006772:Hospitals, Military; D006801:Humans; D032023:Integrons; D008297:Male; D008875:Middle Aged; D058889:Molecular Typing; D020613:Morganella morganii / Q000145:classification / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D010957:Plasmids; D016133:Polymerase Chain Reaction; D011513:Proteus mirabilis / Q000145:classification / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D015363:Quinolones / Q000494:pharmacology*; D017422:Sequence Analysis, DNA; D014416:Tunisia; D047090:beta-Lactams / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D015363:Quinolones; D047090:beta-Lactams