Background: Mucosal‐associated Escherichia coli may play a role in the pathogenesis of inflammatory bowel diseases (IBDs). In this study we assessed mucosal‐associated E. coli in adults at the time of first diagnosis.
Materials and Methods: E. coli were isolated from 59 right colon biopsies of 34 newly diagnosed adult IBD patients (Crohn's disease [CD] = 23, ulcerative colitis [UC] = 11) and 25 healthy controls (HC). Strains were serotyped, phylotyped into A, B1, B2, or D, and tested for their ability to survive in macrophages. The presence of various virulence factors was also assessed. The fimH subunit of type 1 fimbriae was sequenced and phylogenetically analyzed.
Results: A total of 65 E. coli were isolated from CD (29 isolates from 23 patients), UC (11 isolates from 11 patients), and HC (25 isolates from 25 subjects). All E. coli were positive for fimH, crl, and cgsA and negative for vt1, vt2, hlyA, cnf, and eae. Significant positive associations were between CD and in between CD and afae (P = 0.002), and between UC and ompA (P = 0.02), afae (P = 0.03), and USP (P = 0.04). The B2+D phylotype was significantly associated with inflammation (P = 0.04) as it was with serine protease autotransporters (SPATE), malX, ompA, and kpsMTII (P < 0.05). Macrophage survival was the highest in UC‐isolated E. coli (P = 0.04). FimH amino acid substitutions N91S, S99N, and A223V were associated with IBD (P < 0.05).
Conclusions: Adherent invasive E. coli are present at first diagnosis, suggesting that they may have a role in the early stages of disease onset. (Inflamm Bowel Dis 2010;)
1 Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Manitoba, Canada
2 Department of Internal Medicine, University of Manitoba, Manitoba, Canada
3 University of Manitoba Inflammatory Bowel Disease Clinical and Research Centre, Manitoba, Canada
4 Department of Biochemistry and Biomedical Sciences, McMaster University, Ontario, Canada
5 Laboratory of Foodborne Zoonoses, Public Health Agency of Canada, Ontario, Canada
6 Department of Animal Science, University of Manitoba, Manitoba, Canada
* 229 Animal Science Building, University of Manitoba, Manitoba R3T 2N2, Canada.
Received 22 August 2010; Accepted 30 August 2010
Published online 9 December 2010 in Wiley Online Library (wileyonlinelibrary.com).
Supported by the grant from the Crohn's and Colitis Foundation of Canada and the University of Manitoba Graduate Fellowship.