Fecal microbiota transplantation for vancomycin-resistant Clostridium innocuum infection in inflammatory bowel disease: A pilot study evaluating safety and clinical and microbiota outcome.

Background: Clostridium innocuum is a vancomycin-resistant pathobiome associated with poor clinical outcomes in inflammatory bowel disease (IBD). In ulcerative colitis (UC), it correlates with reduced remission rates, while in Crohn's disease (CD), it is linked to creeping fat formation and intestinal strictures. Notably, some patients experience refractory or recurrent C. innocuemailum infections despite metronidazole treatment. This study evaluates the safety and efficacy of single-dose fecal microbiota transplantation (FMT) in IBD patients with refractory or recurrent C. innocuum infections.

Methods: We conducted a feasibility pilot study involving seven IBD patients (3 CD, 4 UC) with refractory (n = 5) or recurrent (n = 2) C. innocuum infections following metronidazole treatment. Patients underwent single-dose FMT and were monitored for six months.

Results: No adverse events were recorded. All participants demonstrated improved disease activity post-FMT, as assessed by the Crohn's Disease Activity Index and Mayo Score. However, a mild increase in symptom severity was noted at six months. Follow-up cultures showed persistent C. innocuum infection in one patient and asymptomatic recurrence in another at three months. Alpha diversity of the gut microbiome increased post-FMT, and Bray-Curtis dissimilarity analysis revealed a microbiota composition more similar to that of the donor.

Conclusion: Single-dose FMT appears to be a safe and feasible therapeutic approach for refractory or recurrent C. innocuum infections in IBD patients, with potential benefits in disease activity and microbiome restoration. Further studies are warranted to optimize long-term outcomes.