Identification by DNA hybridisation of enterotoxigenic Escherichia coli in homes of children with diarrhoea.

The DNA hybridisation technique to detect genes coding for Escherichia coli enterotoxin was used to identify enterotoxigenic E coli (ETEC) in homes of children with diarrhoea in Thailand. ETEC was found in 30 (14%) of 221 children with diarrhoea and in 9% (8/88) of their household contacts, 8% (8/101) of their neighbours, and 2% (32/1379) of inhabitants of 382 homes not associated with ETEC infections. ETEC was found significantly more often in water and food and on mothers' hands in homes of children with ETEC-associated diarrhoea and of their neighbours than in homes of children without ETEC infections (8/360 vs 3/2290; p less than 0.001). ETEC was identified in 80% (71/89) of specimens that hybridised with the enterotoxin gene probes by testing E coli isolated from the same specimen in the Y-1 adrenal and suckling-mouse assays. The DNA hybridisation assay to detect genes coding for E coli enterotoxin is an effective method of identifying ETEC in a large number of human and environmental specimens and will be a valuable tool to define further the epidemiology of this enteric pathogen.