The molecular survey of intI gene and antibacterial resistant in avian pathogenic Escherichia coil

Integrons are mobile genetic factors that are able to carry resistance gene in some bacteria like Escherichia coli. Drug resistance study in pathogenic bacteria is important. The aim of this study was to investigate the prevalence of integron class 1 and antibiotic susceptibility pattern in Escherichia coli strains isolated from broilers with colibacillosis infection. A total of 100 Avian Pathogenic Escherichia coli (APEC) were isolated from the lesions of the birds suspected to colibacillosis by sampling aseptically from internal organs. All isolates of Escherichia coli were confirmed by biochemical tests. To evaluate antimicrobial resistance, the disc diffusion method on Mueller-Hinton agar was used in accordance with the Clinical and Laboratory Standards Institute (CLSI) guidelines by using of seven antibacterial paper discs. The DNA of these isolates was extracted by a boiling method and was screened for the presence of class 1 integron gene by conventional polymerase chain reaction (PCR). Antimicrobial resistance test showed resistance to nalidixic acid (100%), tetracycline (96%), ciprofloxacin (91%), norfloxacin (88%), lincospectin (53%), cefuroxime (50%) and gentamicin (17%). Furthermore, 97% of the isolates contained integron class 1. According to the results of this study, there is high prevalence of integron gene in Escherichia coli isolated from colibacillosis lesions. Besides, high prevalence of drug resistance was observed among the isolated pathogenic Escherichia coli.