Secondary Prophylaxis of Clostridium Difficile Infection

Eligibility Details: Inclusion Criteria: - Patients admitted to Tampa General Hospital or outpatients at Infectious Disease Associates of Tampa Bay clinics who are receiving systemic antibiotics and have a history of at least one episode of CDI that was diagnosed on or after 4/1/2017. - Participants must at least 18 years of age to participate. - Participants must be able to understand and sign a written informed consent form prior to initiation of study procedures. - Expected to receive at least 3 days of systemic antibiotics. - Life expectancy greater than 6 months. Exclusion Criteria: - Current CDI - Completion of treatment for CDI within the last 15 days - Concurrent use of drugs that have activity against C. difficile such as metronidazole, fidaxomicin, nitazoxanide, tigecycline, or rifaximine - Concurrent use of cholestyramine - Concurrent use of bezlotoxumab - Concurrent use of probiotics - Concurrent use of Imodium or other antidiarrheal agents. - Chronic suppressive antibiotics - Condition which causes chronic diarrhea such as inflammatory bowel disease - Bacterial gastroenteritis other than CDI - Pregnancy or breastfeeding - Allergy to oral Vancomycin - Inability to take enteric medications - Have an unstable or life limiting condition on admission - Already participating in another study