The purpose of this study is to evaluate the efficacy and safety of Bio-K + CL1285 versus placebo in the prevention of antibiotic-associated diarrhea in hospitalized adult patients.

Antibiotic-associated diarrhea (AAD) is one of the most frequent adverse events following antibiotherapy and is the leading cause of diarrhea in hospitalized patients. Ten to 25% of AAD are caused by the bacteria Clostridium difficile.

A recent unicenter study conducted at Maisonneuve-Rosemont hospital demonstrated the preventive role of Bio-K + CL1285 in antibiotic-associated diarrhea and Clostridium difficile-associated diarrhea. Its preventive role is thought to be mainly through restoration of the gastrointestinal flora affected in part by the antibiotherapy.

A wide body of literature reveals clinical use of probiotics, but few well controlled prospective studies conducted on large numbers of subjects have been performed.

In light of the positive preliminary results obtained in a limited number of patients with AAD and of the paucity of well controlled clinical trials, we now wish to undertake a randomized, double blind, multicentre study to evaluate the efficacy and safety of Bio-K + CL1285 prophylaxis vs. placebo in the prevention of antibiotic-associated diarrhea in hospitalized adult patients. As secondary objectives, we also intend to evaluate the incidence of Clostridium difficile-associated diarrhea and to demonstrate that BIO-K + CL1285 agent will not only improve the clinical outcomes but also reduce health care expenditures.

Inclusion Criteria:

• presenting to the Emergency Room and considered for admission to hospital for a minimum of 12 hours and requiring antibiotic administration for the treatment of a suspected or proven bacterial infection OR a hospitalized patient developing a suspected or proven nosocomial infection OR an external patient that come to the hospital for repeated visits to receive his intravenous antibiotic therapy for the treatment of a suspected or proven bacterial infection. The external patients on oral antibiotics that come to the hospital for repeated visits to receive any other treatments requiring a hospital stay of more than one hour will also be included.
• Hospital employee on antibiotics can also be included in the study
• having received less than 24 hours of antibiotic therapy;
• requiring a minimum of 3 days and a maximum of 14 days antibiotic administration

Informed consent must be obtained in writing for all subjects at enrollment into the study

Exclusion Criteria:

Subjects presenting with any of the following will not be included in the study:

• active diarrhea;
• a history of daily consumption of fermented milk and/or yogurt;
• intolerance to lactose;
• pregnant/breastfeeding women;
• an active, non controlled intestinal disease such as Crohn's Disease or ulcerative colitis;
• ileostomy, jejunostomy or colostomy;
• immunosuppressed state;
• a previous documented C. difficile infection in the three months prior to study initiation;
• active radiotherapy or chemotherapy;
• recent (< 6 months) or planned bone marrow graft or organ transplant;
• antibiotic therapy in the fourteen days prior to study initiation;
• the planned administration of metronidazole (alone or in combination) or vancomycin monotherapy for the treatment of an infection;
• mental or other conditions, or language barriers rendering the subject unable to understand the nature, scope, and possible consequences of the study or complete the self-administered questionnaires;
• subject unlikely to comply with protocol, e.g., uncooperative attitude, inability to return for follow-up visits, and unlikelihood of completing the study.

Post-enrollment exclusion criteria include fermented milk and/or yogurt consumption during the study period and two consecutive missed dose of study product.