[Efficacy of Fecal Microbial Transplantation for Improving Symptoms of Irritable Bowel Syndrome - A Pilot Study for Voluntary Participants in Korea].

Background/aims: Irritable bowel syndrome (IBS) is a chronic, intractable functional disease. It is inferred that fecal microbiota transplantation (FMT) may have favorable efficacy on IBS by gut microbial modification. The aim of this study was to investigate the efficacy of FMT for improving severity in patients with IBS.

Methods: Patients who voluntarily wanted FMT were consecutively enrolled. The study subjects were classified by subtype of IBS by the ROME IV criteria. The IBS-symptom severity score (IBS-SSS) was used to evaluate the efficacy of FMT. The subjects completed a questionnaire at baseline week 0 and weeks 4, 12, and 24 after FMT. FMT was performed by esophagogastroduodenoscopy using frozen stock stool solution. If the follow-up IBS-SSS achieved less than 75 points, it was defined as remission. Adverse events were also gathered.

Results: Twenty-one subjects were included from October 2023 until July 2024. There were 7 patients with IBS-C, 10 patients with IBS-D, 2 patients with IBS-M, and 2 patients with IBS-U type. The mean SSS of the IBS-D group was 244.0±64.2, which was higher than IBS-C group (192.9±85.4). Alleviations in IBS-SSS after FMT were observed in 19 subjects (19/21, 90.5%) at week 4. At week 12, 71.4% (5/7) in the IBS-C group and 20.0% (2/10) in the IBS-D group achieved remission. The remission states were maintained up to week 24 and no serious adverse events were reported.

Conclusions: FMT might be an effective treatment option for improving symptoms of mild to moderate IBS, especially IBS-C.