Oligonucleotide gene probes may detect enterotoxigenic Escherichia coli directly in fecal smears.

ABSTRACT

Diarrhoeal stools from 86 Indian children were examined for the presence of enterotoxigenic Escherichia coli (ETEC) by DNA hybridization on bacterial colonies as well as directly on fecal smears. Colony hybridization showed that 8 of the samples contained ETEC. Only in three of these specimens were all the colonies tested positive for ETEC. These samples were correctly identified by the stool smear hybridization assay. The remaining 5 specimens produced enterotoxigenic as well as nonenterotoxigenic colonies. These samples were all negative by the stool smear hybridization technique. Methodological improvements of the stool smear assay may provide a substantially simplified method for the otherwise cumbersome identification of ETEC.