Fecal Microbiota Transplantation for Inflammatory Bowel Disease: Where We Stand and What Is Next.

Background: Fecal microbiota transplantation (FMT) is an emerging therapeutic strategy for inflammatory bowel disease (IBD). Every step of the FMT process, from donor recruitment and patient selection to pretreatment protocols, administration techniques, and post-FMT interventions, can significantly influence treatment outcomes. These components are interrelated, and even subtle differences in methodology may affect the overall efficacy of FMT for IBD. This review aimed to outline the current clinical experience and findings regarding FMT for IBD during the application process. Summary: Donor screening has traditionally focused on safety. In recent years, although safety remains essential, increasing attention has been paid to the donor selection efficacy. Particularly, identifying patients who are most likely to benefit from FMT is crucial because timely and appropriate patient selection can prevent delays in effective treatment. Pretreatment strategies and FMT procedures remain hot topics of current research. Approaches, such as antibiotic pretreatment, may enhance microbial engraftment; however, the optimal antibiotic combination remains unclear. Bowel lavage is commonly used to reduce the microbial burden and facilitate donor microbiota colonization, whereas corticosteroid pretreatment has shown conflicting results. There are various routes of administration, and oral capsules are gaining popularity owing to their safety and patient acceptability. Stool preparation factors, including the use of single versus pooled donors, anaerobic processing, and storage form (fresh, frozen, or freeze-dried), can significantly influence microbial viability and clinical outcomes. Repeated FMTs tend to be more effective than single infusions; nonetheless, the optimal frequency remains unclear. Post-FMT interventions, such as dietary modifications and supplementation with prebiotics, such as pectin and alginic acid, are also promising strategies. Key Messages: Despite encouraging results, variations in treatment protocols, donor characteristics, and host factors continue to obscure the definitive predictors of FMT success. Further randomized controlled trials and mechanistic studies are required to standardize these procedures and optimize their long-term efficacy.