Recurrent Clostridioides Difficile Infection (rCDI)

The goal of this clinical trial is to learn if oral lyophilized fecal microbiota therapy (ORAL-LYO-FMT) helps treat diarrhea-predominant irritable bowel syndrome (IBS-D) and prevent the recurrence of Clostridioides difficile infection (rCDI). The main questions it aims to answer are: * Does ORAL-LYO-FMT reduce IBS symptoms? * Does it prevent rCDI after treatment? * What side effects or safety concerns might occur? Researchers will compare ORAL-LYO-FMT to a placebo (a look-alike capsule with no active treatment) to see how well it works. Participants will: * Be randomly assigned to take ORAL-LYO-FMT or placebo for up to 7 weeks * Take capsules three times per week (Monday, Wednesday, Friday) * Complete health questionnaires and have follow-up visits by phone or in person for up to 6 months The trial also looks at changes in quality of life, mood, and new or ongoing medical conditions over time.