title: Patchy distribution of mucosal lesions in ileal Crohn's disease is not linked to differences in the dominant mucosa-associated bacteria: a study using fluorescence in situ hybridization and temporal temperature gradient gel electrophoresis.
abstract: BACKGROUND
  The mucosa-associated bacteria (MAB) are suspected of being involved in the pathogenesis of Crohn's disease. We analyzed and compared the MAB in noninflamed and inflamed ileal mucosa of Crohn's disease patients (n = 22).
  
  
  METHODS
  Tissue samples from the inflamed ileal mucosa and from the adjacent noninflamed ileal mucosa were taken from surgical resection specimens. The MAB were investigated using fluorescence in situ hybridization with 7 group-specific probes and temporal temperature gradient gel electrophoresis (TTGE).
  
  
  RESULTS
  Samples from both noninflamed and inflamed mucosa were obtained from 15 patients. The distribution of the bacterial populations was not different between noninflamed and inflamed mucosa. The Bacteroidetes phylum was dominant and accounted for 29% of MAB (0%-74%) in noninflamed tissues and 32% (0%-70%) in inflamed areas. The gamma Proteobacteria represented 12% (0%-70%) of MAB both in noninflamed and inflamed areas. The Clostridium coccoides group (Firmicutes phylum) represented 15% of MAB in noninflamed tissues versus 7% in inflamed areas. For most of the patients the similarity index between TTGE paired profiles was very high.
  
  
  CONCLUSIONS
  The dominant MAB do not differ between noninflamed and inflamed ileal mucosa in Crohn's disease. This argues against a localized dysbiosis to explain the patchy distribution of mucosal lesions.
authors.affiliation: Laboratoire de Biologie EA 3199, CNAM, 2 rue Conté 75003 Paris, France.
authors.forename: Nadia
authors.initials: N
authors.lastname: Vasquez
authors.forename: Irène
authors.initials: I
authors.lastname: Mangin
authors.forename: Patricia
authors.initials: P
authors.lastname: Lepage
authors.forename: Philippe
authors.initials: P
authors.lastname: Seksik
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Duong
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Blum
authors.forename: Eduardo
authors.initials: E
authors.lastname: Schiffrin
authors.forename: Antonia
authors.initials: A
authors.lastname: Suau
authors.forename: Matthieu
authors.initials: M
authors.lastname: Allez
authors.forename: Gwenola
authors.initials: G
authors.lastname: Vernier
authors.forename: Xavier
authors.initials: X
authors.lastname: Tréton
authors.forename: Joël
authors.initials: J
authors.lastname: Doré
authors.forename: Philippe
authors.initials: P
authors.lastname: Marteau
authors.forename: Philippe
authors.initials: P
authors.lastname: Pochart
mesh_terms: D000328:Adult; D001419:Bacteria / Q000235:genetics* / Q000302:isolation & purification*; D001706:Biopsy; D015169:Colony Count, Microbial; D003424:Crohn Disease / Q000188:drug therapy / Q000382:microbiology* / Q000473:pathology; D004269:DNA, Bacterial / Q000032:analysis*; D004311:Double-Blind Method; D004586:Electrophoresis / Q000379:methods; D005260:Female; D006801:Humans; D007082:Ileum / Q000382:microbiology* / Q000473:pathology; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D007413:Intestinal Mucosa / Q000382:microbiology* / Q000473:pathology; D007778:Lactobacillus; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D019936:Probiotics / Q000627:therapeutic use; D013696:Temperature
chemical_list: D004269:DNA, Bacterial