IDDF2024-ABS-0232 Washed microbiota transplantation: a salvage therapy strategy for severe gut infection caused by specific pathogen beyond CDI

<h3>Background</h3> Antibiotic resistance and limited treatment options for severe pathogenic intestinal infections beyond <i>Clostridioides difficile</i> infection (CDI) pose a growing challenge. The purpose of this study is to investigate the potential therapeutic benefits of washed microbiota transplantation (WMT) in patients suffering from severe intestinal infections that are not responding to conventional treatment. <h3>Methods</h3> Severe patients with definite evidence of refractory gut infection beyond CDI undergoing WMT therapy were involved from September 2015 to August 2022. Clinical cure was defined as a total abdominal symptom score (TASS) equal to zero at seven days post-rescue or gut infection. The evidence turned negative after WMT, with TASS after WMT being less than or equal to three points. Clinical improvement was defined as a decrease in abdominal symptom scores by more than 3 points or less than or equal to 1 point seven days after WMT. Nonresponse was defined as persistent abdominal symptoms at seven days post-WMT. As exploratory outcomes, we illustrated these patients’ adverse events and clinical outcomes at 12-week follow-up. <h3>Results</h3> Ten patients with definite gut infection evidence who underwent 32 rescue WMTs were included (IDDF2024-ABS-0232 Figure 1. Flowchart of the study). 50% (5/10) of patients obtained clinical cures after WMT. 20% (2/10) patients achieved clinical improvement and 30% (3/10) patients turned out to be nonresponse seven days after WMT. The survival rates in the clinical cure group, clinical improvement group, and nonresponse group at 12 weeks are (5/5)100%, (1/2) 50%, and (1/3)33.3%, respectively. TASS was significantly reduced seven days after WMT compared with TASS before WMT (Wilcoxon signed rank test, <i>p</i>=0.007). Patients’ scores of defecations declined significantly (Wilcoxon signed rank test, <i>p</i>=0.039) (IDDF2024-ABS-0232 Figure 2. Efficacy of WMT rescue). One patient had transient, probably WMT-related AEs during follow-up, and no serious AE occurred within 12 weeks of follow-up (IDDF2024-ABS-0232 Figure 3. Conditions of patients before and after WMT rescue therapy). <h3>Conclusions</h3> This study provides evidence of WMT for refractory gut infection caused by specific pathogens beyond CDI, which demonstrates the rescue value of WMT for managing severe refractory intestinal infections.