Other virulence factors related to enteric and/or extraenteric infections in domestic animals, such as the cnf-1 and cnf-2 cytotoxins, papG, sfaC/D, and afaB/C fimbriae and iucD (aerobactin) and hly genes [28], were not detected in the 32 E. coli strains assessed in this study, indicating that E. coli may not be a typical primary agent of colitis or enterocolitis in foals [17]. This evidence concerns the gene PAPOLG and colitis.