Global and Deep Molecular Analysis of Microbiota Signatures in Fecal Samples from Patients with Irritable Bowel Syndrome – Source: Gastroenterology, Aug 4, 2011
By M Fajilic-Stojanovic, W M de Vos, et al.
Background & Aims: Irritable bowel syndrome (IBS) has been associated with disruptions to the intestinal microbiota, but studies have had limited power, coverage, and depth of analysis. We aimed to define microbial populations that can be used to discriminate the fecal microbiota of patients with IBS from that of healthy subjects and correlate these with IBS intestinal symptom scores.
Methods: The microbiota composition was assessed by global and deep molecular analysis of fecal samples from 62 patients with IBS patients and 46 healthy individuals (controls). We used a comprehensive and highly reproducible phylogenetic microarray in combination with quantitative PCR.
The intestinal microbiota of IBS patients differed significantly ( P =.0005) from that of controls. [That is, the odds of this difference resulting by chance are 1 in 100,000.]
The microbiota of patients, compared with controls, had a 2-fold increased ratio of the Firmicutes to Bacteroidetes ( P =.0002). [Note: other studies have associated an elevated proportion of Firmicutes with the elderly GI tract, which in turn is typically linked to reduced digestive secretions, slower gut transit time, reduced energy production and weight gain.]
This resulted from:
• An approximately 1.5-fold increase in numbers of Dorea, Ruminococcus, and Clostridium spp. ( P <.005); [Types of Firmicutes]
• A 2-fold decrease in the number of Bacteroidetes ( P <.0001);
• A 1.5-fold decrease in numbers of Bifidobacterium and Faecalibacterium spp. ( P <.05); [Bifidobacteria are considered helpful ‘probiotics’ and faecalibacteria have an anti-inflammatory effect.]
• And, when present, a 4-fold lower average number of methanogens (3.50x10(7) vs 8.74x10(6) cells/g feces; P =.003). [Methanogens are involved in the production of ATP – the fuel that the mitochondria burn to produce cellular energy.]
Correlation analysis of the microbial groups and IBS symptom scores indicated the involvement of several groups of Firmicutes and Proteobacteria in the pathogenesis of IBS. [Proteobacteria are gram-negative bacteria, including many that are pathogenic.]
• Global and deep molecular analysis of fecal samples indicates that patients with IBS have a different composition of microbiota.
• This information might be used to develop better diagnostics and ultimately treatments for IBS.
Source: Gastroentrology, Aug 4, 2011. PMID: 21820992, by Rajili?-Stojanovi? M, Biagi E, Heilig HG, Kajander K, Kekkonen RA, Tims S, de Vos WM. Laboratory of Microbiology, Wageningen University, Wageningen, The Netherlands; Department for Biotechnology and Biochemical Engineering, Faculty of Technology and Metallurgy, University of Belgrade, Belgrade, Serbia; Departments of Veterinary Biosciences and Bacteriology & Immunology, University of Helsinki, Finland. [Email: email@example.com]