The aim of this work was to verify the presence of seven virulence factors (ST. LT, eae, stx(1), stx(2), INV and EAEC) among Escherichia coli strains isolated from healthy humans, bovines, chickens, sheep, pigs and goats, from two sewage treatment plants and from the Tiete River. We have found a high prevalence of eae, stx(1) and stx(2) in ruminants. the EAEC gene was only found in humans and sewage. No strains presented ST, LT or INV. BOX-PCR fingerprints revealed a high diversity among the strains analysed and a non-clonal origin of strains that presented the same virulence factors. Therefore, we concluded that ruminants may constitute an important reservoir of most diarrheagenic E. coli in Brazil, except for EAEC strains. These results emphasize the importance of the identification of the animal source of fecal contamination for the correct water risk assessment.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Univ Estadual Campinas UNICAMP, Ctr Biol Mol & Engn Genet, BR-13083875 Campinas, SP, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Microbiol Imunol & Parasitol, BR-04023062 São Paulo, BrazilCo Ambiental Estado São Paulo CETESB, Dept Anal Ambientais, BR-05459900 São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Microbiol Imunol & Parasitol, BR-04023062 São Paulo, BrazilFAPESP: FAPESP 2007/55312-6FAPESP: FAPESP 2007/57025-4Web of Scienc
