[Verocytotoxigenic Escherichia coli: several aspects... and also the dairy farms]

Verocytotoxigenic Escherichia coli (VTEC) is associated with outbreaks and sporadic cases of hemorrhagic colitis (HC) and hemolytic-uremic syndrome (HUS), the most severe form of these human diseases. In Argentina HUS is endemic, with 500 new cases per year and an incidence of 17/100,000 in children under 5 years of age. VTEC O157:H7 is the most frequently isolated serotype, although there are non-O157 serotypes that have been associated with human disease. VTEC produces verocytotoxins and accessory virulence factors such as intimin, an enterohemolysin and an autoagglutinating protein called Saa. Cattle are VTEC carriers and several studies in Argentina have confirmed that bovines are the main reservoir of serotypes O157:H7 and non-O157, many of them involved in HUS and HC worldwide. Transmission of VTEC to humans occurs through consumption of undercooked meat, vegetables and water contaminated by feces of carriers, person-to-person and contaminated environment contact. Dairy farms can contribute to the risk of VTEC infection in humans through the consumption of raw milk, dairy products, and contaminated meat from dairy cattle and through contamination of the dairy environment. There is wide distribution and high prevalence of VTEC serotypes in dairy cattle in Argentina; therefore, it is important to improve the measures of control and management and to prevent the transmission of VTEC strains among animals, environment and humans.