RESUMO
AIM: This work aimed to determine the occurrence of antibiotic and disinfectant resistance genes in Escherichia coli isolated from chickens in Egypt. MATERIALS AND METHODS: Organs (liver, lung, heart, yolk sac, and bone marrow) of 1500 chicken samples were collected from diseased chickens suffered from colibacillosis with PM findings as CRD, diarrhea and omphalitis from different governorates of Egypt as: Giza, EL-Bahira, Fayoum, El-Dakahlia, El-Ismalia, and El-Sharkia during 2015-2016. These samples were labeled and transported immediately on ice to the Reference laboratory for quality control on poultry production (RLQP). The samples were cultured onto MacConkey agar and Eosin Methylene Blue Agar. Isolation and identification of the E. coli were performed based on morphology, cultural, staining, and biochemical properties. Antimicrobial resistance test was carried out using disk diffusion method. The PCR employing tetA, qacED1 and qacA/B were carried out for detection of these genes in isolated E.coli. RESULTS: The prevalence of E. coli in chicken was 34%. Predominant serotypes of E. coli which serologically identified were O128, O111, O44, O158, and O2. Antibiotic susceptibility test of E. coli revealed that 100% of isolates were resistant to ampicillin, erythromycin, and sulfamethoxazole-trimethoprim, while 73.53% and 38.23% of them were sensitive for colistin sulfate and levofloxacin, respectively. Antibiotic resistance genes as tetA gene were tested for isolated E. coli and detected by incidence rate of 91.18%. qac resistance genes resembling as qacED1 and qacA/B genes were detected in isolated E. coli 70.6% and 14.7%, respectively. CONCLUSION: E. coli isolated from chickens in Egypt was carried qac and antibiotic-resistant genes that affect the poultry industry.