Acta Veterinaria Eurasia
Original Article

Phylogenetic Grouping of Verotoxigenic Escherichia coli (VTEC) Obtained from Sheep and Broiler Chicken in Northwestern Iran

1.

Department of Microbiology, Faculty of Veterinary Medicine and Department of Cellular and Molecular Biotechnology, Institute of Biotechnology, Urmia University, Urmia, Iran

2.

Department of Microbiology, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran

Acta Vet Eurasia 2018; 44: 53-58
DOI: 10.26650/actavet.2018.010
Read: 188 Downloads: 73 Published: 03 May 2018

Verotoxigenic Escherichia coli (VTEC) are major foodborne pathogens with an increasing public health concern. The purpose of this study was to investigate the occurrence and the phylogenetic groups of VTEC isolates from the feces of healthy sheep and broiler chickens at a slaughterhouse in Urmia region, Northwestern Iran. A total of 446 E. coli isolates (97 from sheep and 349 from broiler chickens) were assessed for the occurrence of the Vtx-encoding genes (vtx1 and vtx2) using polymerase chain reaction. Then, all the recovered VTEC isolates were phylogenetically grouped based on the Clermont phylotyping method using three genetic sequences, the so-called chuA, yjaA, and TSPE4.C2. The vtx gene-carrying E. coli was identified in 46.4% (45/97) of sheep-originated isolates and in 8.3% (29/349) of broiler chicken-originated isolates. In general, phylotyping revealed that 74 VTEC isolates segregated in the phylogenetic groups A (32.4%; designated as VTEC-A), B1 (44.6%; VTEC-B1), B2 (9.5%; VTEC-B2), and D (13.5%; VTEC-D). The results also showed that the dissemination of VTEC isolates of sheep and broiler chicken origin varied noticeably in their assignment to B1 and D phylogenetic groups (p<0.01). In addition, the virulent phylogenetic groups (B2 and D) were significantly more common in broiler chickens than in sheep (p<0.01). In conclusion, healthy sheep and broiler chickens could be a reservoir for VTEC belonging to virulent phylogenetic groups, thus representing a potential risk factor for public health. This study also demonstrated significant differences with respect to the phylogenetic group assignment of the VTEC strains between sheep and broiler chickens.

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ISSN 2618-639X EISSN 2619-905X