Sampling and diversity of Escherichia coli from the enteric microbiota in patients with Escherichia coli bacteraemia.

Enteric samples from E. coli bacteraemia patients yielded a median of one E. coli RAPD pattern (range 1-4) compared with two (range 1-5) from groups without E. coli bacteraemia. Of relevance to large-scale clinical studies, observed diversity of E. coli among hospitalised patients was not altered by sample type (rectal swab or stool), nor by increasing the colonies tested from 10 to 20. Hospitalised patients demonstrated an apparently limited diversity of E. coli in the enteric microbiota and this was further reduced in those with E. coli bacteraemia. The reduced diversity of E. coli within the gut during E. coli bacteraemia raises the possibility that dominant strains may outcompete other lineages in patients with bloodstream infection.