title: Quantification and characterization of mucosa-associated and intracellular Escherichia coli in inflammatory bowel disease.
abstract: BACKGROUND
  Mucosa-associated Escherichia coli are abundant in inflammatory bowel disease (IBD), but whether these bacteria gain intracellular access within the mucosa is uncertain. If E. coli does gain intracellular access, the contribution of bacterial pathogenicity to this requires further elucidation. This study aimed to quantify and characterize mucosa-associated and intracellular E. coli in patients with IBD and in healthy control subjects (HC).
  
  
  METHODS
  Mucosal biopsies from 30 patients with Crohn's disease (CD), 15 with ulcerative colitis (UC), and 14 HC were cultured with or without gentamicin protection to recover intracellular or mucosa-associated E. coli, respectively. Overall, 40 strains (CD: n = 24, UC: n = 9, and HC: n = 7) were characterized by phylogenetic typing, adhesion and invasion assays, detection of virulence factors, antimicrobial resistance genes, and proteomic analysis.
  
  
  RESULTS
  Mucosa-associated E. coli were more abundant in CD and UC than in HC (2750 versus 1350 versus 230 median colony-forming units per biopsy; P = 0.01). Intracellular E. coli were more prevalent in CD (90%) than in UC (47%) or HC mucosal biopsies (0%) (P < 0.001). Of 24 CD strains, 2 were adherent and invasive, but there were no unifying pathogenicity determinants that could distinguish most CD strains from UC or HC strains, or intracellular isolates from mucosa-associated isolates.
  
  
  CONCLUSIONS
  Intracellular E. coli are more common in CD than in UC and not identified in HC. Most intracellular E. coli did not have characterizing pathogenic features, suggesting a significant role for defects in mucosal immunity or barrier dysfunction in their ability to gain intracellular access.
authors.affiliation: *Diabetes and Nutritional Sciences Division, King's College London, London, United Kingdom; †Department of Gastroenterology, Guy's and St. Thomas' NHS Foundation Trust, St Thomas' Hospital, London, United Kingdom; ‡Department of Medicine, University of Melbourne, Melbourne, Australia; §Animal Health and Veterinary Laboratories Agency, Surrey, United Kingdom; and ‖US Department of Agriculture, Agricultural Research Service, Western Regional Research Center, Produce Safety and Microbiology Research Unit, Albany, California.
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Elliott
authors.forename: Barry N
authors.initials: BN
authors.lastname: Hudspith
authors.forename: Guanghui
authors.initials: G
authors.lastname: Wu
authors.forename: Michael
authors.initials: M
authors.lastname: Cooley
authors.forename: Gareth
authors.initials: G
authors.lastname: Parkes
authors.forename: Beatriz
authors.initials: B
authors.lastname: Quiñones
authors.forename: Luke
authors.initials: L
authors.lastname: Randall
authors.forename: Robert E
authors.initials: RE
authors.lastname: Mandrell
authors.forename: Clifton K
authors.initials: CK
authors.lastname: Fagerquist
authors.forename: Jonathan
authors.initials: J
authors.lastname: Brostoff
authors.forename: Neil B
authors.initials: NB
authors.lastname: Rayment
authors.forename: Alex
authors.initials: A
authors.lastname: Boussioutas
authors.forename: Liljana
authors.initials: L
authors.lastname: Petrovska
authors.forename: Jeremy D
authors.initials: JD
authors.lastname: Sanderson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001422:Bacterial Adhesion; D015415:Biomarkers / Q000378:metabolism*; D018938:Caco-2 Cells; D016022:Case-Control Studies; D002478:Cells, Cultured; D003093:Colitis, Ulcerative / Q000235:genetics / Q000276:immunology / Q000382:microbiology*; D003424:Crohn Disease / Q000235:genetics / Q000276:immunology / Q000382:microbiology*; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000235:genetics / Q000276:immunology / Q000382:microbiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007413:Intestinal Mucosa / Q000276:immunology / Q000382:microbiology*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D020543:Proteome / Q000032:analysis; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D037521:Virulence Factors / Q000032:analysis; D055815:Young Adult
chemical_list: D015415:Biomarkers; D004269:DNA, Bacterial; D020543:Proteome; D037521:Virulence Factors