The prevalence and genomic context of Shiga toxin 2a genes in E. coli found in cattle

Strains of Shiga toxin-producing E. coli (STEC) that cause severe forms of disease like the haemolytic uraemic syndrome (HUS), referred to as “HUSEC”, predominantly carry the toxin gene variant stx2a. However, the role of Shiga toxin in the ruminant reservoirs of this zoonotic pathogen is poorly understood and strains that cause disease in humans likely constitute a small and atypical subset of the overall STEC flora. The aim of this study was to investigate the presence of stx2a in samples from cattle and to characterize stx2a-positive isolates of E. coli from cattle.