STX2 and hemolytic-uremic syndrome: Possession of OI-122, OI-43/48 and the non-LEE effector genes together with stx2, eaeA and a complete plasmid is a hallmark of highly virulent STEC strains that are frequently associated with outbreaks and severe disease such as HC and HUS [11,56,57], whereas serotypes lacking these genes are mostly implicated in mild human disease [11,32,57,58].