Clostridioides difficile infection (CDI) is associated with substantial morbidity and mortality. Patients at greatest risk are typically older, hospitalized and/or with multiple comorbidities. Fecal microbiota transplantation (FMT), a method aimed to restore the composition and diversity of gut’s microbiota, has been recently approved for treating refractory CDI or recurrent CDI (rCDI), after a second recurrence that did not respond to conventional antibiotics. Current evidence suggests that FMT is a safe therapeutic method with few adverse effects, although, protocol optimization and long-term outcomes have not been completely elucidated.

We conducted a retrospective longitudinal analysis of all patients who underwent FMT in our department between 2017 and 2025. A rigorous selection of potential unrelated/cohabiting donors was carried out. All procedures were performed under aseptic conditions, ensuring that no more than 6 hours elapsed between the collection of fresh donor stools and the FMT execution. Demographic data, comorbidities, prior treatments, clinical outcomes (efficacy and safety), and follow-up data were collected.

Ten patients underwent FMT during the study period. The indication was rCDI for all cases. All procedures were performed via colonoscopy, with instillation of donor fecal solution into the ileum and cecum. The median age was 72.8±12.1 years-old ; 70% (n=7) of patients were men . The mean Charlson Comorbidity Index was 6.4±2.8. Type 2 diabetes was the most common comorbidity, followed by ulcerative colitis. Patients had experienced an average of 3.6±1.0 prior CDI episodes before FMT. The mean interval between the first CDI episode and FMT was 15.6±19.1 months with a range from 3 to 50 months. Three patients were receiving immunosuppressive therapy. All patients had been previously treated with antibiotics, the most frequent being vancomycin, followed by fidaxomicin and metronidazole. All patients responded to one-single FMT with an overall success rate of 100% and no CDI recurrence. Median follow-up was 6(1-24) months. Five patients died during follow-up, three of them within 6 months of the procedure (due to pulmonary infection, suspected disseminated metastatic disease and non-Hodgkin B-cell lymphoma). No adverse events were registered. No deaths were attributed to CDI or the FMT.

FMT proved to be effective and safe even in high-risk patients, including those who were chronically immunosuppressed, had inflammatory bowel disease and multiple and significant comorbidities. In case of refractory/recurrent CDI, repeat FMT via another route and/or another fecal donor may be considered. Mortality during follow-up was related to underlying comorbid conditions rather than FMT. Larger studies are need to further assess the outcomes and consider the use of frozen stool capsules from universal stool donor banks.