The majority of the strains analyzed carried stx1 as the sole stx type, and most of them showed the genotype 1a. This finding may partly explain the reason for which STEC infections in Brazil are mostly sporadic and of non-complicated nature, diverging from other countries where many of the reports about STEC pathogens involved in outbreaks and HUS are caused by strains carrying only stx2, with the predominance of two genotypes, 2a and 2c [50,51]. This evidence concerns the gene STX2 and hemolytic-uremic syndrome.