Colibacillosis in lambs and kids in Egypt: Prevalence, serogroups, antibiogram profile, virulence genes distribution and antimicrobial resistance genes

BACKGROUND: Small ruminants have a socioeconomic impact on Egypt’s production of meat, milk, and wool. Hence, every effort should be taken to prevent infections. AIM: To elucidate the prevalence and serogrouping of Escherichia coli (E. coli) strains from diarrheic lambs and kids, determine their antibiotic susceptibility and associated risk factors affecting the occurrence of the disease, and establish the most common virulence genes marker and major antimicrobial resistance genes. METHODS: A total of 150 diarrheic animals (95 lambs and 55 kids) at different ages and seasons were subjected to clinical examination. Rectal swabs were collected from 150 diarrheic animals for isolation and biochemical identification of E. coli. RESULTS: The bacteriological examination revealed that 62/95 lambs and 26/55 kids with percentages of 65% and 47%, respectively, showed infection with E. coli. Serotyping of 88 isolates of E. coli revealed the strains belonging to O2(8), O55(17), O84(5), O17(4), O6(8), O91(17), O26(9), O103(5), O126(5), O124(6), and O159(4). A total of 21 isolates were examined by multiplex polymerase chain reaction assay for detection of virulence and resistance genes. All examined isolates possessed a combination between intimin gene and heat-stable toxin (100%), the serine protease (pic) gene on 8/21 isolates of O55, O2, O6 (38%), and α-hemolysin gene on 8/21 isolates of O26, O91(38%) while adherent invasive gene (invA) gene on 3/21 isolates of O124, O159 (14%) which divided diarrheagenic E. coli into four types assigned to be atypical enteropathogenic E. coli (48%), atypical enterohemorrhagic E. coli 35%), atypical enterotoxigenic E. coli (6%), and atypical enteroinvasive E. coli (11%). On the other hand, the results of antimicrobial susceptibility testing revealed high resistance to ampicillin, erythromycin, and tetracycline (100%) and amoxicillin/clavulanic acid (92%) but were highly sensitive to gentamicin, imipenem, norfloxacin, ciprofloxacin, chloramphenicol, and amikacin (100%). Concerning to ß lactams antibiotic resistance genes of examined isolates had blaSHV (100%) and blaCTX-M (43%). For tetracycline, we detected the tetA in all examined isolates. CONCLUSION: The wide spread of atypical E. coli strains among diarrheic lambs and kids with marked resistance to several antibiotics of interest and the detection of major resistance genes assess the potential risk of this pathogen to animal and public health.