title: Characterization of Escherichia coli isolated from gut biopsies of newly diagnosed patients with inflammatory bowel disease.
abstract: 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.
  
  
  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.
authors.affiliation: Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Manitoba, Canada.
authors.forename: Shadi
authors.initials: S
authors.lastname: Sepehri
authors.forename: Ehsan
authors.initials: E
authors.lastname: Khafipour
authors.forename: Charles N
authors.initials: CN
authors.lastname: Bernstein
authors.forename: Brian K
authors.initials: BK
authors.lastname: Coombes
authors.forename: Ana V
authors.initials: AV
authors.lastname: Pilar
authors.forename: Mohamed
authors.initials: M
authors.lastname: Karmali
authors.forename: Kim
authors.initials: K
authors.lastname: Ziebell
authors.forename: Denis O
authors.initials: DO
authors.lastname: Krause
mesh_terms: D000328:Adult; D003093:Colitis, Ulcerative / Q000235:genetics / Q000382:microbiology*; D003424:Crohn Disease / Q000235:genetics / Q000382:microbiology*; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D004927:Escherichia coli Infections / Q000235:genetics / Q000382:microbiology*; D006801:Humans; D007413:Intestinal Mucosa / Q000382:microbiology*; D016133:Polymerase Chain Reaction
chemical_list: D004269:DNA, Bacterial