STX2 and infection: In the Stx2 group, stx2a, stx2c, and stx2d were reported to be more virulent in human infections compared to isolates carrying stx2b, stx2e, stx2f, and stx2g (Burgos and Beutin, 2012; Probert et al., 2014; Zhi et al., 2019; Bai et al., 2021).