show Abstracthide AbstractHeteropathogenic Shiga toxin (Stx)-producing Escherichia coli (STEC) of multilocus sequence type (MLST ST) 141 cause both urinary tract infection and diarrhea in humans. We could show previously that they possess virulence genes typical for STEC and uropathogenic E. coli (UPEC) and are phylogenetically positioned between these pathogroups. However the origin and evolution of these strains are unknown.