Abstract
The aerobic gram-negative microbiota and virulence properties of Escherichia coli were studied in 157 rectal biopsy specimens from 50 patients with a first attack of inflammatory bowel disease (IBD) and in 56 such specimens from 20 patients with infectious colitis or infectious-type colitis (non-relapsing colitis, NRC). E. coli strains that produced both haemolysin, enterohaemolysin or colicin were found to a similar extent in IBD and NRC. E. coli strains carrying recognised virulence factors, such as enterotoxins and adhesins, were rarely isolated from patients of either group. No property was found more often in active than in inactive phases of the disease. In addition, the properties of E. coli were evenly distributed between ulcerative colitis and Crohn's disease. E. coli strains belonging to classical enteropathogenic or enteroinvasive serotypes were not isolated. Non-motile E. coli lacking H antigen were isolated to a similar extent in IBD and NRC. Repeated isolation of the same serotype of E. coli was more common in IBD (P<0.05).