However, STEC strains that lack the eae gene can also cause severe disease by utilising alternative adherence mechanisms, as evidenced recently during a large outbreak of HUS in Germany in 2011 and caused by an enteroaggregative haemorrhagic Escherichia coli (EAHEC) O104:H4 carrying the aggR and aaiC genes in combination with stx2a [25]. Here, STX2 is linked to hemolytic-uremic syndrome.