Of these, five contained stx2 alone, and as described by Friedrich et al. [31], stx2 is clinically and epidemiologically the most important Shiga-toxin type, and the probability of HUS development in infections from strains harbouring stx2 is higher than that from strains containing either stx1 or both stx1 and stx2. This evidence concerns the gene STX2 and infection.