VIRULENCE PROPERTIES OF ESCHERICHIA-COLI ISOLATED FROM THE RECTAL MUCOSA OF PATIENTS WITH FIRST ATTACKS OF COLITIS

The aerobic gram-negative microbiota and virulence properties of Esche richia coli were studied in 157 rectal biopsy specimens from 50 patien ts with a first attack of inflammatory bowel disease (IBD) and in 56 s uch specimens from 20 patients with infectious colitis or infectious-t ype colitis (non-relapsing colitis, NRC). E. coli strains that produce d 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 t han 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 e nteroinvasive serotypes were not isolated. Non-motile E. coli lacking H antigen were isolated to a similar extent in IBD and NRC. Repeated i solation of the same serotype of E. coli was more common in IBD (P<0.0 5).