STX2 and hemolytic-uremic syndrome: Although the role of free Stx2 in the pathogenesis of EHEC-HUS has been demonstrated in numerous studies that applied to experimental animals purified Stx2 alone or with LPS (Tesh et al., 1993; Palermo et al., 2000; Keepers et al., 2006; Rasooly et al., 2010; Porubsky et al., 2014; Dennhardt et al., 2018), the pathogenetic involvement of Stx2-containing OMVs is poorly understood.