Investigation of virulence factors of shiga toxin-producing Escherichia coli strains isolated from sheep

Abstract

All over the world, Escherichia coli (STEC), which produces Shiga toxin, is recognized as an important zoonotic pathogen. Ruminants, particularly cattle, are their main reservoirs, but the role of small ruminants in the epidemiology of human infections has not been extensively evaluated in many countries. In this study, it was aimed to determine the Shiga toxin subtypes of Stx1, Stx2, eae and ehxa genes of Shiga toxin producing isolates within Escherichia coli strains in sheep and to determine the comparative effect of variables such as race and sex on them. In this study, virulence genes of STEC strains and Shiga toxin subtypes were identified in 215 E. coli isolates isolated from 272 rectal swab from 12 different sheep herds in and around Ankara. Of the 215 isolates, only 19 (8.84%) Stx1, 3 (1.4%) Stx2, 5 (2.33%) eae and 9 (4.19%) ehxa genes, 13 (6%, 05) Stx1-Stx2-ehxa, 5 (2.33%) Stx1-eae -ehxa, 3 (1.4%) Stx2-eae-ehxa together and 1 (0.47%) Stx1- eae, 30 (13.95%) Stx1- ehxa, 1 (0.47%) Stx2- eae, 15 (6.98%) Stx2-ehxa and 10 (4.65%) eae – ehxa were detected together. Of the 101 (46.98%) isolates, none of the Stx1, Stx2, eae and ehxa genes were detected. In stx1 subtyping in sheep, a high rate (82.35%) of stx1c was isolated. In stx2 subtyping stx2f (%62,86), stx2c (%54,29), stx2b (%45,71), stx2d (%22,86), stx2h (%22,86) subtypes are more common in different combinations. Detected at a high rate. These data indicate the presence of STEC in sheep and their potential to cause serious infection in humans