Prevalence and virulence profile of avian pathogenic E.coli isolated from clinically diseased broiler chickens

Abstract

Escherichia coli plays a part in maintaining intestinal physiology. Although, there are pathogenic strains that cause different syndromes of diarrheal disease. E. coli strains are the cause of a number of diseases in broiler chickens, leading to death, decrease in production or condemning of carcasses. This study aimed to determine phenotypes and virulence associated genes of avian pathogenic Escherichia coli (APEC) recovered from diseased and freshly dead chickens including, shiga toxin 1, shiga toxin 2 and intimin using genotypic methods. A total of 200 chicken visceral organs (liver, lungs, spleen and heart) collected from diseased and freshly dead birds (four organs per each bird) were subjected for conventional culturing, serotyping and molecular characterization of virulence genes. 32 (16%) of isolates were biochemically identified as E.coli and confirmed by PCR using phoA gene. O78, .O8, O145 and O1 are the most prevalent serotypes from APEC isolates. stx1 and stx2 were determined by multiplex PCR , while eae gene was detected by uniplex PCR . stx2 gene was detected in 50% ( 16/32), while, 81.26% (26/32) of APEC isolates harbored eae. stx1 was not detected in all the tested isolates. The obtained results demonstrated the importance of studies in E. coli of avian origin in regions associated with intensive poultry industry, aiming to evaluating the predominant strains and also acquiring preventive measures to minimize losses due to APEC.