First molecular detection of shiga toxin-producing Escherichia coli in dogs from serbia: a potential threat to human health?

Shiga toxin‑producing Escherichia coli (STEC) are considered one of the most significant E. coli pathotypes transmitted by food, causing life‑threatening conditions in children and elderly people. The aim of this study was to investigate the presence and determine the prevalence of STEC in dogs in Serbia by conventional PCR method, targeting three major virulence genes (stx1, stx2, and eae). The overall percentage of positive samples was 12.87% (13/101), with the stx2 gene, the more potent of the two toxins, found in all the positive samples. The finding of eae gene in combination with stx genes (8/13) within the same genetic pool implies the potential presence of enterohemorrhagic E. coli or the potential emergence of these strains, considering an efficient mechanism of horizontal transfer of three major virulence genes. Our results also highlight dogs' lifestyle as a risk factor for STEC colonisation. These E. coli strains, according to our results, are more likely to be found in dogs living outdoors than those kept in house. Due to significant prevalence of STEC in dogs determined in this research and due to close contact between dogs and humans, dogs could be considered a source of human infections.