title: Plasmid mediated quinolone resistance determinants qnr, aac(6')-Ib-cr, and qep in ESBL-producing Escherichia coli clinical isolates from Egypt.
abstract: OBJECTIVE
  To characterize the prevalence of plasmid-mediated quinolone resistance determinants qnr, aac(6')-Ib-cr and qep in extended-spectrum β-lactamase (ESBL) -producing E. coli and to determine the association of these determinants with CTX-M group in Cairo, Egypt.
  
  
  METHODS
  MICs of 15 antimicrobial agents against 70 E. coli clinical isolates were determined using agar dilution technique according to CLSI. Screening for the qnrA, qnrB, qnrS, aac(6')-Ib, qep and CTX-M genes was carried out by PCR amplification and DNA sequencing. Curing was used to confirm whether qnr, aac(6')-Ib, qep or ESBL-encoding genes were located on plasmids.
  
  
  RESULTS
  Out of 70 E. coli clinical isolates, 61 were resistant to at least one antibiotic, 16 (22.8%) were multidrug resistant and 30 (42%) were ESBL producers. Out of 30 ESBL producers E. coli isolates, 8 (26.6%) were positive for qnr genes, and the qnrA1-, qnrB1-and qnrS1-type genes were detected alone or in combination in 5 (16.6%), 7 (23.3%) and 5 (16.6%) isolates, respectively. Seven (23.3%) isolates were positive for aac(6')-Ib-cr and only two (6.6%) isolates were positive for qepA4. Loss of all plasmids upon curing suggested that qnr, aac(6')-Ib-cr , qep A4 and ESBL-encoding genes were always plasmid mediated. Out of 8 Qnr positive isolates 5 were associated with both CTX-M-1 and CTX-M-9 while 2 from 6 aac(6')-Ib-cr positive isolates were associated with both CTX-M-1 and CTX-M-9.
  
  
  CONCLUSIONS
  This study highlights the prevalence of quinolone resistance determinants qnr, aac(6')-Ib-cr , qep A4 associated with CTX-M positive E. coli isolates from Egypt. This is the first report of the plasmid mediated fluoroquinolone efflux pump, Qep A from Egypt.
authors.affiliation: Department of Microbiology and Immunology, Faculty of Pharmacy, Helwan University, Egypt.
authors.forename: W M
authors.initials: WM
authors.lastname: Hassan
authors.forename: A
authors.initials: A
authors.lastname: Hashim
authors.forename: Raa
authors.initials: R
authors.lastname: Domany
mesh_terms: D000123:Acetyltransferases / Q000235:genetics; D000617:Aminoglycosides / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D024901:Drug Resistance, Multiple, Bacterial; D004534:Egypt / Q000453:epidemiology; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology*; D029968:Escherichia coli Proteins / Q000235:genetics; D006801:Humans; D008826:Microbial Sensitivity Tests; D010957:Plasmids; D016133:Polymerase Chain Reaction; D015995:Prevalence; D015363:Quinolones / Q000494:pharmacology*; D001618:beta-Lactamases / Q000235:genetics; D047090:beta-Lactams / Q000494:pharmacology*
chemical_list: D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D029968:Escherichia coli Proteins; C485384:Qnr protein, E coli; D015363:Quinolones; D047090:beta-Lactams; D000123:Acetyltransferases; C056532:aminoglycoside N(6')-acetyltransferase; D001618:beta-Lactamases