Detection of Plasmid-Mediated Quinolone and ?-lactam Resistant Genes in Escherichia Coli Isolates from Diseased Poultry in Egypt

Escherichia coli bacteria are normal inhabitant in the intestine of man, animals and poultry. A total of 20 isolates of E. coli ?, isolated from diseased chickens belonged to different O-serogroups and showed resistance to one or more antibiotics, were investigated for antimicrobial resistance against ?-lactam and quinolone groups of antibiotics and tested for detection of plasmid mediated quinolone resistant genes. The result was resistance of 60% of the isolates to ampicillin and amoxicillin (?-lactam group) and 95%, 85%, 80%, 45% and 20% to enrofloxacin, norfloxacin, naldixic acid, danofloxacine and ciprofloxacin (quinolone group), respectively. All the selected isolates showed multi-resistance when they were tested against 8 antibiotic groups. Among the twenty E. coli ? isolates tested, 6 (30%) isolates were positive for the qnr genes, where 5 (25%) isolates were positive for qnrS gene; one of them was positive for qnrB gene and only one isolate carried qnrA gene. All the E. coli ? isolates were negative for aac (6’)-Ib-cr gene. On the other hand, the qep?A gene was the most commonly found in the PMQR genes, as it was detected in 14 (70%) E. coli ? isolates. All qnr positive isolates carried the qep?A gene. The ?-lactam resistant gene (blaTEM was detected in 16 (80%) of the isolates; while the blaSHV gene was detected only in one isolate. There was a high correlation between the presence of the qep?A gene and resistance to ENR, NA, and NOR, as well as between and blaTEM gene and resistance to AML and AMP.