A total of 70 Escherichia coli strains were isolated from samples
(liver and heart) collected from diseased chickens (n=105) in about
21 commercial farms located in Suez Canal district of Egypt during
May-July 2012. We investigated the susceptibility to Flouroquinolones
(Ciprofloxacin, Enrofloxacin and Norfloxacin) and 9 other
antibacterials (Gentamicin, Streptomycin, Doxycyclin, Amoxicillin,
Ampicillin, Cephazolin, Cephradine, Lincomycin, Florfenicole) by
disc diffusion method and measured the MIC of ciprofloxacin and
enrofloxacin. Resulted flouroquinolones resistant E.coli isolates were
then serotyped, and investigated for the prevalence of plasmidmediated
fluoroquinolone resistance (PMQR) genes (qnrA, qnrB,
qnrS, aac(6`)-Ib-cr, and qepA) by polymerase chain reaction. Among
the E.coli isolates, 72.8% (51/70) were resistant to Ciprofloxacin and
Enrofloxacin with MIC ≥ 4 and ≥ 2 (μg/ml) respectively. These isolates were resistant also to at least 6 other investigated
antibacterials in the study for susceptibility/resistance. Among the
resistant 51 E.coli strains, 36 (70.5%) were positive for PMQR genes,
27 (52.9%) were positive for at least one gene of the qnr genes
investigated in the study, 16 (31.37%) were positive for qnrA, qnrB
and qnrS separately, 20 (39.2%) were positive to aac(6`)-Ib-cr, 35
(68.6%) were positive to qepA, while 4 (7.8%) harbored all the 5
investigated genes. The resistance of E. coli to flouroquinolones has
been increasing in the past twenty years but unfortunately no enough
data about isolates harboring PMQR genes in Egypt either in human
or poultry field. Further investigations concerning the antimicrobial
resistance problem in human and veterinary field in Egypt is
recommended as a surveillance program is a must.