The role of the gut microbiome in the pathogenesis and treatment of IBS is increasingly recognized. The observation that an acute gastroenteritis increases the likelihood of developing IBS as well as the identification of intrinsic differences in the microbiome of IBS patients relative to healthy controls support the suggestion that disturbances in the microbiome can lead to IBS.
Further, multiple microbiome-based treatments including diet, prebiotics, probiotics and antibiotics have been found to be beneficial for subsets of patients with IBS. Successes with these treatments have stoked speculation about the potential benefits of fecal microbial transplant (FMT) as a treatment for IBS patients. The stunning success of FMT for patients with recurrent C. difficile infection has further fanned the flames around this debate.
Indeed, multiple randomized controlled trials (RCTs) have assessed FMT vs. sham FMT in IBS patients. The results have been summarized in two recently published meta-analyses. In the meta-analysis by Xu et al, when data from four RCTs was aggregated, FMT was found to be no more effective than sham FMT (RR = 0.93; 95% CI, 0.48–1.79). The second meta-analysis by Ford et al came to a similar conclusion based upon data from five RCTs.
However, in an analysis based on mode of administration of FMT, it was found that colonoscopic administration offered benefits for IBS (RR = 0.98; 95% CI, 0.58–1.66) while FMT administered as oral capsules or naso-jejunal tube did not. As none of the trials directly compared the different modes of FMT administration and other factors (eg, donor, dose, timing of administration), the results of this post-hoc, subgroup analysis should be viewed as hypothesis generating and will require confirmation in a properly designed and powered, comparative effectiveness trial.
The small study by Singh et al adds to this growing body of literature. This study casts doubt on the benefit of pre-FMT antibiotics. Additionally, this study provides further evidence against the value of FMT using oral capsules for IBS. For now, FMT for IBS should be considered experimental. More studies are needed to determine if colonoscopically administered FMT is beneficial IBS. It will also be interesting and important to explore whether profiling of the gut microbiome or metabolome might serve as a biomarker that could enrich the likelihood of response to FMT and more generally, microbiome-based treatments.
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Xu D, et al. Am J Gastroenterol. 2018;10.14309/ajg.0000000000000198.
William D. Chey, MD
Director of the GI Physiology Laboratory
University of Michigan Health System
Disclosures: Chey reports financial ties to Allergan, Conti, IM Health, Ironwood, MyGiHealth, Nestle, QOL Medical, Ritter, Salix, Shire, True Self Foods, Volcant and Zespori.