Serotyping and Virulence Genes Detection in Escherichia coli Isolated from Broiler Chickens

Abstract

Background and Objective: Escherichia coli (E. coli) strains causing systemic disease in poultry (avian colibacillosis) are termed avian pathogenic E. coli (APEC). Colibacillosis is a disease of severe economic significance to all poultry producers worldwide and is characterized by a diverse array of lesions. Escherichia coli that cause infections usually possess one or more virulence properties that may help in establishment of the infection. The aim of this study was to investigate the virulence genes in E. coli isolated from broiler chickens. Methodology: A total number of 125 chicken samples from apparently healthy broiler chickens (25 and 15), diseased broiler chickens (25 and 15) and freshly dead ones (25 and 20) were collected in winter (from December, 2014 to February, 2015) and summer (from June, 2015 to August, 2016), respectively from Kafr El-sheikh Governorate. Results: In winter season, E. coli was recovered from 43 broiler chickens with an incidence of 57.3% and the incidence of E. coli in apparently healthy broiler chickens was 32%, diseased broiler chickens 64% and in freshly dead ones 76% while in summer season E. coli was recovered from 21 broiler chickens with an incidence 42% represented 26.6% in apparently healthy, 40% in diseased chickens and 55% in freshly dead one. The serogroups of E. coli that obtained by serological identification were O78, O1, O26, O2, O127, O91 and O153. The results obtained by multiplex PCR reported that eaeA (intimin E. coli attaching and effacing) gene detected in O2, O26, O1 and O153, ompA (outer membrane protein) gene detected in all E. coli serogroups that isolated O2, O26, O78, O127, O1 and O91 except O153. Stx1 gene detected in O2, O26, O78 and O91. Stx2 gene detected in O78, O127 and O91. Conclusion: The present study showed a higher percentage of E. coli isolates carrying at least one virulence gene.