title: Effect of a multispecies probiotic supplement on quantity of irritable bowel syndrome-related intestinal microbial phylotypes.
abstract: BACKGROUND
  Probiotics can alleviate the symptoms of irritable bowel syndrome (IBS), possibly by stabilizing the intestinal microbiota. Our aim was to determine whether IBS-associated bacterial alterations were reduced during multispecies probiotic intervention consisting of Lactobacillus rhamnosus GG, L. rhamnosus Lc705, Propionibacterium freudenreichii ssp. shermanii JS and Bifidobacterium breve Bb99. The intervention has previously been shown to successfully alleviate gastrointestinal symptoms of IBS.
  
  
  METHODS
  The faecal microbiotas of 42 IBS subjects participating in a placebo-controlled double-blind multispecies probiotic intervention were analysed using quantitative real-time polymerase chain reaction (qPCR). Eight bacterial targets within the gastrointestinal microbiota with a putative IBS association were measured.
  
  
  RESULTS
  A phylotype with 94% similarity to Ruminococcus torques remained abundant in the placebo group, but was decreased in the probiotic group during the intervention (P = 0.02 at 6 months). In addition, the clostridial phylotype, Clostridium thermosuccinogenes 85%, was stably elevated during the intervention (P = 0.00 and P = 0.02 at 3 and 6 months, respectively). The bacterial alterations detected were in accordance with previously discovered alleviation of symptoms.
  
  
  CONCLUSIONS
  The probiotic supplement was thus shown to exert specific alterations in the IBS-associated microbiota towards the bacterial 16S rDNA phylotype quantities described previously for subjects free of IBS. These changes may have value as non-invasive biomarkers in probiotic intervention studies.
authors.affiliation: Department of Veterinary Biosciences, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland.
authors.forename: Anna
authors.initials: A
authors.lastname: Lyra
authors.forename: Lotta
authors.initials: L
authors.lastname: Krogius-Kurikka
authors.forename: Janne
authors.initials: J
authors.lastname: Nikkilä
authors.forename: Erja
authors.initials: E
authors.lastname: Malinen
authors.forename: Kajsa
authors.initials: K
authors.lastname: Kajander
authors.forename: Kyösti
authors.initials: K
authors.lastname: Kurikka
authors.forename: Riitta
authors.initials: R
authors.lastname: Korpela
authors.forename: Airi
authors.initials: A
authors.lastname: Palva
mesh_terms: D000328:Adult; D001419:Bacteria / Q000235:genetics* / Q000302:isolation & purification; D004269:DNA, Bacterial / Q000032:analysis*; D019587:Dietary Supplements; D004311:Double-Blind Method; D005243:Feces / Q000382:microbiology; D005260:Female; D006801:Humans; D007422:Intestines / Q000382:microbiology*; D043183:Irritable Bowel Syndrome / Q000188:drug therapy* / Q000382:microbiology; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D019936:Probiotics / Q000008:administration & dosage*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D004269:DNA, Bacterial