STX1A and hemolytic-uremic syndrome: For instance, one study estimated that 59.1% of patients infected with stx1-positive STEC experienced diarrhea, with none presenting with HUS; in contrast, the authors observed a higher rate of diarrhea in 68.8% of patients infected with stx2-positive STEC, of which 12.5% also progressed to HUS [44].