Clostridioides difficile (CD) infection (CDI) is a global health threat with an urgent need for new treatment strategies. Faecal microbiota transplantation (FMT) is effective for recurrent Clostridioides difficile infection (CDI), and is currently recommended for multiple (three or more), recurrent CDI infections. The role of FMT earlier in the treatment hierarchy of CDI remains to be determined.

In this randomized, double-blinded, placebo-controlled clinical trial, we compare FMT with placebo following standard antibiotic treatment for first or second Clostridioides difficile infection.

This is a parallel arm placebo-controlled clinical trial. We aim to include 84 adult patients with their first or second episode of Clostridioides difficile (formerly Clostridium difficile) infection. All patients receive vancomycin standard therapy. Patients are randomised in a 1:1 ratio to two treatments with capsules that contain either FMT+FMT or placebo+placebo. The primary outcome is absence of C difficile-associated disease 8 weeks after randomisation. Patients who have fulminant disease where it is deemed unethical to give placebo are offered open-label FMT. The primary outcome in patients with fulminant C difficile infection is 8 weeks mortality.

Inclusion Criteria:

• 1. or 2. CDI (within a year) defined as: > 3 bowel movements of Bristol 6-7 per day and positive stool CD-test.
• Age 18 years or higher.

Exclusion Criteria:

• Pregnancy
• Does not speak or understand the Danish language
• Current antibiotic treatment other than vancomycin
• Current treatment with potential interations with vancomycin
• Allergy to vancomycin
• Previous anaphylactic reactions due to food allergies
• Continuous need for proton pump inhibitor
• Documented gastroparesis
• Fulminant CDI

Data may be obtained in a anonymous form compliant with the General Data Protection Regulation (GDPR)