Association of symptoms with gastrointestinal microbiota in irritable bowel syndrome

• Published in: World journal of gastroenterology : WJG Vol. 16; no. 36; pp. 4532 - 4540
• Main Author: Malinen, Erja
• Format: Journal Article
• Language: English
• Published: United States Baishideng Publishing Group Co., Limited 28.09.2010
• Subjects: Adult; Aged; Bacteria - genetics; Feces - microbiology; Female; Gastrointestinal Tract - microbiology; Humans; Irritable Bowel Syndrome - microbiology; Irritable Bowel Syndrome - physiopathology; Male; Metagenome - genetics; Middle Aged; Original; Principal Component Analysis; RNA, Ribosomal, 16S - genetics; Surveys and Questionnaires; Young Adult
• ISSN: 1007-9327; 2219-2840; 2219-2840
• DOI: 10.3748/wjg.v16.i36.4532

To investigate the correlations between self-reported symptoms of irritable bowel syndrome (IBS) and the gastrointestinal (GI) microbiota composition. Fecal samples were collected from a total of 44 subjects diagnosed with IBS. Their symptoms were monitored with a validated inflammatory bowel disease questionnaire adjusted for IBS patients. Thirteen quantitative real-time polymerase chain reaction assays were applied to evaluate the GI microbiota composition. Eubacteria and GI bacterial genera (Bifidobacterium, Lactobacillus and Veillonella), groups (Clostridium coccoides/Eubacterium rectale, Desulfovibrio desulfuricans) and distinct bacterial phylotypes [closest 16S rDNA sequence resemblance to species Bifidobacterium catenulatum, Clostridium cocleatum, Collinsella aerofaciens (C. aerofaciens), Coprococcus eutactus (C. eutactus), Ruminococcus torques and Streptococcus bovis] with a suspected association with IBS were quantified. Correlations between quantities or presence/absence data of selected bacterial groups or phylotypes and various IBS-related symptoms were investigated. Associations were observed between subjects' self-reported symptoms and the presence or quantities of certain GI bacteria. A Ruminococcus torques (R. torques)-like (94% similarity in 16S rRNA gene sequence) phylotype was associated with severity of bowel symptoms. Furthermore, among IBS subjects with R. torques 94% detected, the amounts of C. cocleatum 88%, C. aerofaciens-like and C. eutactus 97% phylotypes were significantly reduced. Interesting observations were also made concerning the effect of a subject's weight on GI microbiota with regard to C. aerofaciens-like phylotype, Bifidobacterium spp. and Lactobacillus spp. Bacteria seemingly affecting the symptom scores are unlikely to be the underlying cause or cure of IBS, but they may serve as biomarkers of the condition.