Efficacy and Safety of Lactobacillus Acidophilus/Rhamnosus Combination for the Prevention of Antibiotic-associated Diarrhea in the Elderly

Inclusion Criteria: * Inpatients over the age of 60 on 4A/B unit at Victoria General Hospital, Victoria BC, and * Anticipated to receive antibiotics (intravenous or oral) for greater than 72 hours for any indication, and * Are determined to be competent by the prescriber. Exclusion Criteria: * Patients who have been on antibiotics during the past 2 weeks * Patients who have active diarrhea at enrollment * Patients who have been diagnosed with CDI within the previous 3 months * Patients who are lactose intolerant * Patients who have an underlying chronic GI tract disease (inflammatory bowel disease, irritable bowel syndrome) * Patients who have an ileostomy or colostomy * Patients who regularly take probiotics * Patients who are severely immunocompromised (HIV positive, transplant patient, on antirejection medications, on a steroid for \>30 days, or chemotherapy or radiotherapy within the last year) * Patients who have a life-threatening illness * Patients who cannot take medications by mouth or are tube fed * Patients who have been on the new antibiotic for more than 72 hours * Patients who are anticipated to receive the new antibiotic for a duration of less than 72 hours * Patients who do no give informed consent.