Distribution of toxigenic Escherichia coli serotypes in the intestines of infants.

As part of an ongoing study into the pathogenesis of sudden infant death syndrome (SIDS), the distribution of serotypes of toxigenic and non-toxigenic Escherichia coli within the gastrointestinal tract of babies who had died was investigated. Escherichia coli isolates from the mid-ileum, colon and rectum of six SIDS cases and one case which had died suddenly and unexpectedly but had underlying cardiac pathology were "O" serogrouped and examined for verocytoxic activity and production of heat-labile enterotoxin. In addition, the effect of storage of gut specimens and rectal swabs at 4 degrees C on isolation of toxigenic strains was studied in three of the cases. A diversity of serogroups and toxigenicity was a general finding, however, strains found in the proximal gut were also cultured from the rectum, indicating that faecal specimens would be a valid tool in investigating the role of these organisms in SIDS cases compared with healthy controls. Storage for up to 5 days at 4 degrees C had no appreciable effect on isolation rates of toxigenic bacteria.