Fecal microbiota transplantation for carbapenem-resistant Pseudomonas spp. colonization in hematology patients: long-term real-world data

OBJECTIVES: Colonization with carbapenem-resistant Pseudomonas spp (CRP) contributes to infections and high mortality. Fecal microbiota transplantation (FMT) offers a strategy for eradicating multidrug-resistant organisms, but experience on CRP decolonization in immunocompromised patients is meagre. DESIGNS AND METHODS: A single-center retrospective study of gastroscopic FMT in CRP-positive hematological patients. The primary objective was decolonization. Short and long-term post-FMT CRP-related infectious complications were evaluated. RESULTS: By April 30, 2025, 14 patients (5 ALL, 5 AML, 2 MDS, 1 APL, 1 NHL) were enrolled; 8 had received allo-HCT. With a median follow-up of 16 months (1.45-26), decolonization was achieved in 10 in a median of 14 days (9-34) and was durable in 6. Eradication failure occurred in 4 due to persistence and 4 due to recurrence. Median time to recolonization was 83 (32-173). 9 patients experienced CRP-related infections following FMT: bloodstream infections (BSI) 67%, soft tissue 56%, gastrointestinal 56%, urinary tract 33%, pneumonia 22%, septic shock 22%. A total of 7 died; due to infections in 6, with CRP responsible in 5. No severe adverse events of FMT were reported. CONCLUSIONS: FMT demonstrates safety and efficacy in early decolonization of CRP. In failure, CRP-related infections remain a leading cause of mortality.