Molecular and phylogenetic insights into multi drug resistant Shiga toxin producing E. coli from calf diarrhoea

Escherichia coli is a ubiquitous member of the gut microbiome. Still, Shiga toxin producing E. coli (STEC) can cause severe diseases, including hemorrhagic colitis and hemolytic uremic syndrome, mediated by stx1 and/or stx2 genes. Domestic ruminants, particularly cattle, are the primary reservoirs of STEC and serve as essential sentinels for antimicrobial resistance (AMR). Owing to high genomic plasticity, E. coli readily acquires mobile resistance elements, with the highest AMR prevalence in young calves during early gut microbiome development. This study employs whole-genome sequencing to characterise STEC from diarrheic calves of Bangladesh, focusing on resistance genes, virulence factors, and phylogenetic relationships.