title: Alterations in the mucosa-associated bacterial composition in Crohn's disease: a pilot study.
abstract: BACKGROUND
  Changes in the intestinal bacterial composition seem to play a major role in the pathogenesis and in the clinical course of inflammatory bowel diseases (IBD), which consist of Crohn's disease (CD), and ulcerative colitis (UC). Mutations in the NOD2 gene are the most important genetic risk factors for the development of CD. In this study, the association between mucosal biopsies and the mucosa-associated bacterial composition from CD and UC patients regarding their genetic risk factors (mutations in the NOD2 gene), their endoscopic activity, and their medical therapy (TNF-α blocking therapy) was examined.
  
  
  METHODS
  Seventy biopsies from routine colonoscopies from 33 IBD patients (26 CD and 7 UC) were obtained. Disease activity and clinical characteristics were assessed. Seven different bacterial strains (Bacteroides fragilis, Escherichia coli, Prevotella melaninogenica, Clostridium coccoides, Clostridium difficile, Bifidobacterium bifidum, and Faecalibacterium prausnitzii) were quantified using real-time PCR. NOD2 genotyping from patients with CD was performed.
  
  
  RESULTS
  Five of the 24 patients were positive for at least one mutation in the NOD2 gene. The bacterial composition was different in CD compared to UC, in macroscopic healthy compared to macroscopic inflamed biopsies, in NOD2 mutated compared to NOD2 wildtype patients, and in patients receiving TNF-α blocking therapy compared to patients without this treatment.
  
  
  CONCLUSIONS
  This study further characterizes the mucosa-associated bacteria in IBD patients. Different clinical situations lead to an altered mucosa-associated bacterial composition. The analyzed bacteria could be promising targets for cost-effective surveillance or therapies in IBD patients.
authors.affiliation: Division of Gastroenterology and Endocrinology, Department of Medicine II, University Medical Center Rostock, Ernst-Heydemann-Str. 6, 18057, Rostock, Germany. holger.schaeffler@med.uni-rostock.de.
authors.forename: Holger
authors.initials: H
authors.lastname: Schäffler
authors.affiliation: Division of Gastroenterology and Endocrinology, Department of Medicine II, University Medical Center Rostock, Ernst-Heydemann-Str. 6, 18057, Rostock, Germany.
authors.forename: Annika
authors.initials: A
authors.lastname: Kaschitzki
authors.affiliation: Division of Gastroenterology and Endocrinology, Department of Medicine II, University Medical Center Rostock, Ernst-Heydemann-Str. 6, 18057, Rostock, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Alberts
authors.affiliation: Division of Gastroenterology and Endocrinology, Department of Medicine II, University Medical Center Rostock, Ernst-Heydemann-Str. 6, 18057, Rostock, Germany.
authors.forename: Peggy
authors.initials: P
authors.lastname: Bodammer
authors.affiliation: Division of Gastroenterology and Endocrinology, Department of Medicine II, University Medical Center Rostock, Ernst-Heydemann-Str. 6, 18057, Rostock, Germany.
authors.forename: Karen
authors.initials: K
authors.lastname: Bannert
authors.affiliation: Institute of Medical Microbiology, Virology and Hygiene, University Hospital Rostock, Rostock, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Köller
authors.affiliation: Institute of Medical Microbiology, Virology and Hygiene, University Hospital Rostock, Rostock, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Warnke
authors.affiliation: Institute of Medical Microbiology, Virology and Hygiene, University Hospital Rostock, Rostock, Germany.
authors.forename: Bernd
authors.initials: B
authors.lastname: Kreikemeyer
authors.affiliation: Division of Gastroenterology and Endocrinology, Department of Medicine II, University Medical Center Rostock, Ernst-Heydemann-Str. 6, 18057, Rostock, Germany.
authors.forename: Georg
authors.initials: G
authors.lastname: Lamprecht
mesh_terms: D000328:Adult; D000368:Aged; D001419:Bacteria / Q000235:genetics / Q000302:isolation & purification*; D001706:Biopsy; D003093:Colitis, Ulcerative / Q000382:microbiology / Q000473:pathology; D003424:Crohn Disease / Q000382:microbiology* / Q000473:pathology*; D005260:Female; D060005:Genotyping Techniques; D006801:Humans; D007413:Intestinal Mucosa / Q000382:microbiology* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D053473:Nod2 Signaling Adaptor Protein / Q000235:genetics; D010802:Phylogeny; D010865:Pilot Projects; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000378:metabolism; D055815:Young Adult
chemical_list: C429018:NOD2 protein, human; D053473:Nod2 Signaling Adaptor Protein; D012336:RNA, Ribosomal, 16S; D014409:Tumor Necrosis Factor-alpha
keywords: Crohn’s disease; IBD; Mucosa-associated bacteria; NOD2; RT-PCR; Ulcerative colitis