Objective: In 10-15% of patients with irritable bowel syndrome (IBS), the onset of symptoms follows a gastrointestinal infection or antibiotic use, which may be caused by alterations of the gut microbiota. We aimed to evaluate the effect of FMT in patients with post-infectious IBS or antibiotic-induced IBS.

Materials and Methods: We performed an open label pilot study (N=10) at the VU University medical center in Amsterdam from August 2016 through January 2017. Participants with therapy refractory post-infectious or antibiotic-induced IBS, with an IBS-Symptom severity score of at least 175 points were eligible. Donor feces was administered via a duodenal tube. Participants were followed for eight weeks via two validated questionnaires: IBS-SSS, and IBS-Quality of Life score (IBS-QOL). Fecal samples were obtained before and after FMT for microbiota analysis. FMT was considered clinically effective if participants reported an IBS-SSS improvement of at least 50 points compared to baseline, at eight weeks after FMT.

Results: FMT was effective in five participants. The median IBS-SSS of all patients improved from 340 (range 230-480) points at baseline to 205 (range 80-470) at eight weeks after FMT (p=0.008). The median IBS-QOL improved from 53% (range 21-77%) to 70% (21-93%) (p=0.008). In general, the microbiota composition of responders shifted to that of their corresponding donors. Non-responders initially also did, however, eight weeks after FMT, the microbiota composition had shifted back towards baseline.

Conclusions: FMT appears as a promising treatment for antibiotic-induced and post-infectious IBS. Based on these results, a randomized placebo controlled trial in this specific subgroup of IBS patients is warranted.