Feasibility and Safety of Washed Microbiota Transplantation as Salvage Therapy for Refractory Non-CDI Gut Pathogens in Critically Ill Patients.

Limited treatment options exist for refractory non-Clostridioides difficile infection (non-CDI) of the gut in critically ill patients; whether washed microbiota transplantation (WMT) is feasible and safe in this heterogeneous population is unknown. We retrospectively analysed prospectively registered consecutive cases (NCT03895593) between September 2015 and August 2022, in which severe non-CDI gut pathogens were identified, and rescue WMT was administered after standard treatment failure. Primary outcomes were the clinical outcome and adverse events graded by CTCAE v5.0. Secondary descriptive outcomes were the change in total abdominal symptom score (TASS) on day 7, microbiological clearance, and 12-week survival. Ten patients underwent 29 WMT infusions. Fifty percentage of patients (5/10) obtained clinical cure after WMT. Twenty percentage of patients (2/10) achieved clinical improvement and 30% (3/10) showed no response 7 days after WMT. One transient WMT-related fever occurred (1/29, 3.45%). No serious WMT-attributed events were observed. TASS decreased significantly (p = 0.007). Microbiological clearance was documented in 3 of 4 patients with available post-WMT stool bacteriological test results. This case series provides preliminary evidence supporting the feasibility and potential efficacy of WMT for refractory non-CDI gut pathogens.