title: [The composition of the gastrointestinal mucosa-associated microbiota in irritable bowel syndrome patients].
abstract: OBJECTIVE
  To investigate and analyse the gastrointestinal mucosal-associated microbiota in the samples from diarrhea-predominant IBS (D-IBS), constipation--predominant IBS (C-IBS) patients and healthy controls.
  
  
  METHODS
  Oral cavity, duodenal, colonic and rectal mucosal samples were obtained from 40 IBS patients (20 C-IBS, 20 D-IBS) and 14 healthy controls. Duodenal and colonic tissue was collected during a flexible duodenoscopy and colonoscopy. Tissue samples were frozen for further molecular analysis. DNA was extracted from all frozen samples and used to identify 29 specific bacterial groups using quantitative real-time PCR (qPCR). A statistical treatment of the received data was performed.
  
  
  RESULTS
  The dominant groups of bacteria of various microbiotops of the gastrointestinal tract in IBS patients and healthy controls were determined. qPCR analysis of duodenal samples demonstrated a reduction in the Bifidobacterium concentration in tissue samples from C-IBS patients when compared to healthy controls (p < 0.05). Analysis of rectal samples demonstrated an increase in concentrations of Faecalibacterium praustnizi (p < 0.05) and a reduction in the concentration of Streptococcus spp. (p < 0.01), Atopobium claster (p < 0.05), Ralstonia spp.+Burkholderia spp (p < 0.05) in tissue samples from D-IBS and C-IBS patients when compared to healthy controls.
  
  
  CONCLUSIONS
  Our molecular data indicate that quantitative differences exist in specific bacterial groups in the microbiota between IBS and healthy subjects. The concentration of representatives of Bacteroidetes phylotypes appeared to be the most stable in various microbiotops of the gastrointestinal tract. Small intestinal bacterial overgrowth in IBS patients was not found. Received data help to suggest correlation with the features of the microbiota with clinical form of IBS.
authors.forename: I D
authors.initials: ID
authors.lastname: Loranskaia
authors.forename: M N
authors.initials: MN
authors.lastname: Boldyreva
authors.forename: O A
authors.initials: OA
authors.lastname: Lavrent'eva
mesh_terms: D000293:Adolescent; D000328:Adult; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D005260:Female; D005753:Gastric Mucosa / Q000382:microbiology*; D006801:Humans; D007413:Intestinal Mucosa / Q000382:microbiology*; D043183:Irritable Bowel Syndrome / Q000235:genetics / Q000382:microbiology*; D008297:Male; D008875:Middle Aged; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods