Shiga toxin (Stx) is one of the major virulence factors involved in E. coli O157:H7 pathogenesis (Melton-Celsa et al. 2012); based on immunoreactivity, toxins are classified as either Stx1 or Stx2 (Strockbine et al. 1986), which damage intestinal epithelial cells and kidneys, causing HC and HUS, respectively (Johannes and Römer 2010). The gene discussed is STX1A; the disease is hemolytic-uremic syndrome.