Outbreaks of cholera-like diarrhoea caused by enterotoxigenic Escherichia coli in the Brazilian Amazon Rainforest

Department of Genetics, Oswaldo Cruz Institute, Avenida Brasil 4365, Rio de Janeiro, CEP: 21045-900, Brazil.
Transactions of the Royal Society of Tropical Medicine and Hygiene (Impact Factor: 1.84). 10/2005; 99(9):669-74. DOI: 10.1016/j.trstmh.2005.03.007
Source: PubMed


The relationship between enteropathogens and severe diarrhoea in the Brazilian Amazon is poorly understood. In 1998, outbreaks of acute diarrhoea clinically diagnosed as cholera occurred in two small villages localized far from the main cholera route in the Brazilian rainforest. PCR was performed on some enteropathogens and heat-labile (LT) and/or heat-stable (STh) toxin genes, the virulence determinants of enterotoxigenic Escherichia coli (ETEC), were detected. Further characterization of ETEC isolates revealed the presence of two clones, one from each outbreak. One presenting serotype O167:H5 harboured LT-I and STh toxin genes and expressed the CS5CS6 colonization factor. The other, a non-typeable serotype, was positive for the LT-I gene and expressed the CS7 colonization factor. The current study demonstrates the importance of molecular diagnosis in regions such as the Amazon basin, where the enormous distances and local support conditions make standard laboratory diagnosis difficult. Here we also show that the mis-identified cholera cases were in fact associated with ETEC strains. This is the first report of ETEC, molecularly characterized as the aetiological agent of severe diarrhoea in children and adults in the Brazilian Amazon Rainforest.

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    • "In this study, all Colombian ETEC strains positive for ST were only positive for the STh variant; no ETEC strains positive for STp were identified. Low frequency of STp ETEC strains was also reported among Brazilian, Bolivian, and Chilean ETEC clinical isolates suggesting that STh toxin predominates among Latin American ETECs [33, 46, 47]. "
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