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Indian J Med Microbiol. 2012 Oct-Dec;30(4):442-7. doi: 10.4103/0255-0857.103766.

Plasmid mediated quinolone resistance determinants qnr, aac(6')-Ib-cr, and qep in ESBL-producing Escherichia coli clinical isolates from Egypt.

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1
Department of Microbiology and Immunology, Faculty of Pharmacy, Helwan University, Egypt.

Abstract

PURPOSE:

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.

MATERIALS AND 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.

PMID:
23183470
DOI:
10.4103/0255-0857.103766
[Indexed for MEDLINE]
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