title: Luminal and mucosal-associated intestinal microbiota in patients with diarrhea-predominant irritable bowel syndrome.
abstract: BACKGROUND
  Recent studies have suggested a role for an altered intestinal microbiota in the pathophysiology of irritable bowel syndrome (IBS). However, no consensus has been reached regarding the association between specific enteric bacterial groups and IBS. The aim of this study was to investigate the fecal and mucosal-associated microbiota using two independent techniques in intestinal samples from diarrhea-predominant IBS (D-IBS) and healthy controls.
  
  
  METHODS
  Fecal and colonic mucosal biopsy samples were obtained from 10 D-IBS patients and 10 healthy controls. Colonic tissue was collected during a un-sedated un-prepped flexible sigmoidoscopy. Fecal and tissue samples were processed immediately upon collection for culture under aerobic and anaerobic conditions or frozen for further molecular analysis. DNA was extracted from all frozen samples and used to enumerate specific bacterial groups using quantitative real-time PCR (qPCR).
  
  
  RESULTS
  Culture analysis of intestinal samples demonstrated a significant reduction in the concentration of aerobic bacteria in fecal samples from D-IBS patients when compared to healthy controls (1.4 × 107 vs. 8.4 × 108 CFUs/g feces, P = 0.002). qPCR analysis demonstrated a significant 3.6 fold increase (P = 0.02) in concentrations of fecal Lactobacillus species between D-IBS patients and healthy controls.
  
  
  CONCLUSIONS
  Our culture and molecular data indicate that quantitative differences exist in specific bacterial groups in the microbiota between D-IBS and healthy subjects.
authors.affiliation: Division of Gastroenterology and Hepatology, Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. yehuda_ringel@med.unc.edu.
authors.forename: Ian M
authors.initials: IM
authors.lastname: Carroll
authors.forename: Young-Hyo
authors.initials: YH
authors.lastname: Chang
authors.forename: Jiwon
authors.initials: J
authors.lastname: Park
authors.forename: R Balfour
authors.initials: RB
authors.lastname: Sartor
authors.forename: Yehuda
authors.initials: Y
authors.lastname: Ringel