Efficacy of Oral Vancomycin Prophylaxis for Prevention of Recurrent Clostridium Difficile Infection

Many patients who have a CDI experience recurrent or relapsing symptoms. The investigators
are studying whether vancomycin in low doses will help prevent further CDI episodes and how
this therapy impacts patients' gastrointestinal microbiome and composition.

Patients with a history of past CDI who are receiving antibiotics for a non-CDI condition
will be invited to participate. Approximately half of the participants will receive a
low-dose capsule of vancomycin and half will receive a placebo. Participants will continue
taking the vancomycin/placebo for 5 days after their prescribed antibiotics end.

Inclusion Criteria:

- Willing to provide informed consent.

- Willing to comply with all study procedures and be available for the duration of the
study.

- Documented diagnosis of at least one CDI within the last 180 days with treatment
completed.

- Currently receiving systemic antibiotics for a non-CDI condition with anticipated
duration of no more than 2 weeks.

- Females of childbearing potential must have a negative pregnancy test prior to
randomization and agree to use adequate contraception prior to randomization, for the
duration of the study, and for 4 weeks following study completion.

- Have received no more than 72 hours of non-CDI antibiotics.

Exclusion Criteria:

- History of hypersensitivity or allergy to oral vancomycin.

- Current use of oral vancomycin

- Patients on concurrent treatment with metronidazole or tetracycline monotherapy for
any indication

- Patients diagnosed with inflammatory bowel disorder (Crohn's disease), or bacterial
gastrointestinal infection cause by agents other than C. difficile (e.g. Salmonella
sp.), toxic megacolon and/or known small bowel ileus.

- Dysphagia (inability to swallow capsules) or unwilling to swallow capsules.

- Major gastrointestinal surgery within 3 months of enrollment (does not include
appendectomy or cholecystectomy).

- Any history of total colectomy or bariatric surgery.

- Unable or unwilling to fulfill study requirements.

- Expected life expectancy < 6 months.

- Patients enrolled in another clinical trial with investigational drugs within 30 days
prior to randomization.

- Women who are pregnant or breast-feeding.

- Any patient deemed not suitable for study participation at the discretion of the study
investigator.

- Diarrhea (3 or more loose stools in a 24 hour period) at enrollment.