Perspectives on Shiga-like Toxin Infections in Argentina ^†

Argentina has the highest frequency of hemolytic uremic syndrome (HUS) in the world (300 cases/year). The risk of HUS in children from 6 to 48 months old is approximately 22/100,000 in Buenos Aires. In Argentina, HUS is the most frequent cause of acute renal damage and the second cause of chronic renal injury in children. We have shown that during the spring/summer season, the incidence of Shiga-like toxin (SLT)-associated bloody diarrhea in children less than 5 years old is 30 to 39%. The risk of HUS in SLT-associated bloody diarrhea is about 4 to 5%; 14% of children with SLT diarrhea developed incomplete HUS. Household contacts of children with HUS are commonly colonized with SLT-producing Escherichia coli (39%), and seroconversion occurs in 42% of these. No evidence of free fecal SLTs was observed in healthy children. In Argentina E. coli serotype O157:H7 has been associated with only 2 to 18% of HUS patients and in 4.5 to 7% of children with bloody diarrhea. Other serotypes were also recognized. About 20% of Argentine children start to eat meat at 5 months old, and 80% of them have meat in their diets at least three times a week. Eighty percent of the meat consumed is undercooked. Few data about the incidence of SLT-producing E. coli in cows in our country are available. E. coli O157:H7 was isolated in only 7.7% of calves aged 1 to 3 weeks with E. coli bacillosis from different farms in Argentina. Preliminary data show that SLT-producing E. coli were also present in stools from healthy animals and in fresh retail ground beef, determined by polymerase chain reaction.