Phenotypic and genotypic identification of flouroquinolones resistant escherichia coli isolated from diseased chicken in Suez Canal District

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.