Antibiotic-associated diarrhea (AAD) is a common adverse drug reaction, occurring in 5-35% of patients, and is of significant consequence to hospitalized patients. Patients who develop AAD are more likely to experience a longer hospital stay, incur higher medical costs, and develop other co-morbidities. Clostridium difficile infection (CDI) accounts for approximately 15-25% of AAD cases and is a significant cause of morbidity and mortality in hospitalized geriatric patients.