Genetically related Escherichia coli strains associated with Crohn's disease

Escherichia coli strains isolated from patients with Crohn's disease (CD) w ith chronic ileal lesions (n=14), early endoscopic recurrent lesions (n=20) , without endoscopic recurrence (n=7), and controls (n=21) were compared by ribotyping. The dendrogram generated by 50 ribotype profile analysis revea led a large cluster of genetically linked E coli strains isolated significa ntly more frequently from patients with chronic and recurrent CD (24/33 pat ients) than from controls (9/21) (p<0.05). Most patients operated on for ch ronic heal lesions (78.5%) harboured E coli strains belonging to cluster A (p<0.002 nu controls). The prevalence of patients with early recurrent lesi ons harbouring E coli strains belonging to this cluster was high but not si gnificant, although 16 strains isolated from eight patients presented the s ame ribotype profile. In this cluster, 21 of 26 strains isolated from patie nts with active CD demonstrated adherent ability to differentiated Caco-2 c ells, indicating that most of the genetically related strains share a commo n virulence trait. Comparison of E coli strains recovered from ulcerated an d healthy mucosa of patients operated on for CD demonstrated in each patien t that a single strain colonised the intestinal mucosa. Our results suggest that although a single E coli isolate was not found in Crohn's ileal mucos a, some genotypes were more likely than others to be associated with chroni c or early recurrent ileal lesions.