Evidence supports the role of adherent invasive Escherichia coli (AIEC) in the pathogenesis of inflammatory bowel disease (IBD). However, little is known about the phylogenetic structure and origin of this group of bacteria. Multi-locus sequence typing (MLST), and fimH sequence analysis were performed to elucidate the phylogenetic relationships between E. coli strains isolated from IBD tissue.
Thirty-six E. coli isolated from IBD patients and healthy individuals were used. MLST analysis of the adk, fumC, gyrB, icd, mdh, purA, and recA housekeeping genes was performed. The fimH gene was also sequenced and phylogenetically analyzed. Biochemical profiling of strains were performed using the API 20 E system.
MLST analysis distinguished 9 new alleles and 11 new sequence types, nearly all of which belonged to IBD isolates. E. coli isolated from IBD patients were more likely to be grouped into separate clonal clusters by eBURST analysis of allelic profiles (P = 0.02). Sequencing of fimH placed putative AIEC strains into the same cluster with the uro-pathogenic E. coli CFT073 and the avian-pathogenic E. coli O1:K1:H7.
MLST analysis suggested that E. coli isolated from IBD patients did not evolve from a unique ancestral background. Together with the fimH sequence we conclude that AIEC represent a group of bacteria that have been able to take advantage of an “IBD microenvironment” and likely shares common genes with extraintestinal pathogens like uro-pathogenic CFT073 and avian-pathogenic O1:K1:H7 E. coli. Future research should focus on genes that are unique to AIEC. Inflamm Bowel Dis 2009
1Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Manitoba, Canada
2Department of Animal Science, University of Manitoba, Manitoba, Canada
3Department of Internal Medicine, University of Manitoba, Manitoba, Canada
4University of Manitoba Inflammatory Bowel Disease Clinical and Research Centre, Winnipeg, Manitoba, Canada
*Reprints: Department of Animal Science, 236 Animal Science Building, University of Manitoba, Winnipeg, R3T 2N2 Canada
Received 19 March 2009; Accepted 23 March 2009
Published online 21 May 2009 in Wiley Online Library (wileyonlinelibrary.com).
Grant sponsor: Crohn's and Colitis Foundation of Canada; Grant sponsor: University of Manitoba Graduate Fellowship.