STX2 and hemolytic-uremic syndrome: Previous reports have documented that the Stx2a, Stx2c, and Stx2d subtypes have been associated with severe disease symptoms, including HUS and bloody diarrhea, as well as with differential toxicities in mammalian cells (Friedrich et al., 2002; Ethelberg et al., 2004; Persson et al., 2007; Manning et al., 2008; Müthing et al., 2009; Fuller et al., 2011; Quiñones and Swimley, 2011).