Dr Liji Thomas, MD More than 90% of Hemolytic uremic syndrome (HUS) cases in children are caused by an enteric infection with the Shiga toxin-producing bacterium E. coli (STEC) strain O57 H7. Other strains may also cause STEC but rarely lead to HUS. The O157 H7 strain infects 1% of healthy cattle, inhabiting the intestine