The biochemical and serological characteristics,
virulence properties, and genetic relatedness of Shiga toxin-producing Escherichia coli
(STEC) strains isolated in São Paulo, from April 1989 through
March 1990, were determined. This is also the first report on clinic findings
of human STEC infections in Brazil. The only three STEC strains identified in
that period were lysine decarboxylase negative, belonged to serotype O111ac: non-motile,
were Stx1 producers, carried the eae
A genes, and 2 of them
also presented the EHEC-hly sequence. The children carrying STEC were all boys,
with less than two years old, and had no previous history of hospitalization.
None of them presented blood in stools. Vomiting, cough and coryza were the most
common clinical manifestations observed. Although the STEC strains were isolated
during summer months, and presented similar phenotypic and genotypic characteristics,
carbohydrate fermentation patterns and PFGE analysis suggested that these diarrheal
episodes were not caused by a single clone.