Animal reservoir and genotipic characterization of Enterohemorrhagic Escherichia coli (EHEC) in Argentina

Background: There is a high prevalence of infection by Enterohemorrhagic Es cherichia coli (EHEC) and patients with hemolytic uremic syndrome (HUS) in Argentina. Aim: To study cattle and pigs as a possible reservoir of EHEC in Argentina. Material and methods: One hundred two healthy animals (68 cattl es and 31 pigs) from a livestock in Argentina, were studied. Stool samples were obtained with a rectal sample. The strains were identified by DNA hybr idization with specific gene probes detecting Shiga-like toxin 1 and 2 (Stx 1, Stx2), and hly, gen related to fimbrial adhesion-associated plasmid. EHE C strains were serogrouped using commercial antisera. Results: EHEC was iso lated from 30 out of 68 bovines cultures (44.1%) and from 25 out of 31 pigs (58.1%). Isolates carrying genes codifying both Stx1 and Sxt2, were observ ed in 50% of cattle and 63.9% of pigs. The gene which codifies for hemolysi n (associated to fimbrial adhesin) was observed in about 41% of EHEC isolat es. Strains belonging to Serogroups O26, O111, and O157 were isolated from cattle, and O111, and O157 from Pigs. Conclusions: The high percentage of E EC in both cattle and pigs and the presence of human infection-associated s erogroups, suggests that these animals are a reservoir of EHEC associated w ith disease in humans (Rev, Med Chile 2000 128: 1335-41).