Advances in Animal and Veterinary Sciences

Research Article
Adv. Anim. Vet. Sci. 8(5): 499-505
Http://dx.doi.org/10.17582/journal.aavs/2020/8.5.499.505
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Dalia M. Sedeek*, Mohamed M. Rady, Hanaa S. Fedawy, Nagwa S. Rabie

Poultry Diseases Department, Veterinary Research Division, National Research Centre, Dokki, Giza, Egypt.

Abstract | To identify the virulence genes of avian pathogenic Escherichia coli (APEC) in chickens. Four strains were isolated from the lung, spleen, and liver of eighty freshly dead suspected birds obtained from poultry farms. Therefore, identified biochemically and serologically. Two isolates of O78, one isolate as O1 and one isolate as O26) were identified. Six virulence genes (ompT, hlyF, iroN, iss, iutA, tsh) were isolated. The iroN (50%) virulence gene was detected in two isolates of serogroups O78a and O78b at 553 base pair (bp), while hlyF (100%) virulence gene was detected in all four isolates of E. coli at 450 bp and the ompT (75%) virulence gene was detected in three isolates serogroups O78a, O78b and O1 at 496 bp. The virulence gene iss (25%) was only detected in one isolate serogroup O78b at 266 bp, while virulence gene iutA (100%) was detected in all four isolates at 300 bp. The virulence gene tsh (25%) was only detected in one isolate serogroup O78b at 620 bp. All six virulence factors were detected in Egyptian E. coli isolate serogroup O78b, then made a sequence of three virulence genes (iss, tsh, and iutA) of an APEC serogroup O78b isolate and submitted in gene bank with preliminary accession number MN328734 to MN328736. These sequences were compared to reference strains. A supreme nucleotide identity (>98%) was noticed in comparing the gene sequences of an Egyptian E. coli isolate O78b and genes of reference strains. The three virulence genes of Egyptian isolate E. coli O78b were highly related to genes of reference strains of other countries.

Keywords | E. coli, Isolation, PCR, Virulence genes, Sequencing, Chickens