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P374. The occurrence of Escherichia coli pathotypes and their relation to the disease activity in patients with Crohn's disease and ulcerative colitis

P374. The occurrence of Escherichia coli pathotypes and their relation to the disease activity in patients with Crohn's disease and ulcerative colitis

L. Gombošová, I. Lazúrová, M. Zakuciová, K. Čurová, M. Kmet'ová, D. Petrášová, L. Siegfried

University hospital, Košice, Slovakia

Aim: Escherichia coli (E. coli) pathotypes are more frequently present in the large bowel of patients with Crohn's disease (CD) and ulcerative colitis (UC). There is little evidence about the relationship between E. coli pathotypes and activity of IBD. Aim was to examine the occurence of pathotypes E. coli in patients with CD and UC and to assess their relation to disease activity.

Methods: 68 patients with CD or UC and 37 control subjects were included. CD was diagnosed in 36 and UC in 32 patients. All patients were divided to groups according to disease activity. Activity of CD was assessed by CDAI index and UC by UCDAI Schroeder. Patients underwent colonoscopic evaluation and two mucosal samples were obtained for microbiological and genetic evaluations. Genes of E. coli were detected by using simplex or multiplex PCR. Enterovirulent E. coli were differentiated into the pathotype categories on the basis of their genotypes, virulence factors and pathogenicity mechanisms. We found CDEC (cell detachment E. coli), DAEC (diffuse adherent E. coli), EPEC (enteropathogenic E. coli), AEEC (attaching effacing E. coli, or atypical EPEC), EIEC (entero invasive E. coli). E. coli strains without genes of virulence were included to nonpathogenic group.

Results: CDEC was the most frequently occured pathotype in UC (47%) unlike in CD it was 27%. The significantly lowest presence (11%) of CDEC pathotypes was in control groups, in contrast to UC (p < 0.05). We did not find the pathotype EIEC in IBD patients. DAEC was the most frequently occured pathotype in CD (16%) in contrast to UC (3%, p < 0.05). In control groups DAEC was in 5%. We followed atypical EPEC, named AEEC. Pathotype AEEC was occured in CD in 11%, in UC in 3%. In control group AEEC was not present. Control group had the significant higher occurence of nonpathogenic E. coli (64.9%) in contrast to CD and UC (p < 0.01 in both correlations). Pathotypes AEEC and DAEC occured only in CD with moderate activity, without presence in CD with mild activity. Presence of AEEC and DAEC pathotypes probably can participate in initiation and perpetuation of chronic bowel inflammation.

Patients with mild UC activity had no enterovirulent E. coli, they had only non pathogenic strains. CDEC was presence in groups with moderate and severe UC activity. Control group with presence of CDEC or DAEC without diarrhoea is the evidence, that for onset of disease the immune dysregulation and genetic predisposition is needed.

Conclusions: CDEC pathotype predominates in UC patients. DAEC and AEEC pathotype were observed predominantly in CD patients. In control group predominates nonpathogenic E. coli strains. Enterovirulent pathotypes of E. coli occured in groups with moderate and severe activity of IBD without presence in mild activity. We proposed, that enterovirulent pathotypes perpetuate and worse the chronic intestinal inflammation. It may be important for the therapy.