No patients enrolled. Identification of patients in allocated timeframe was not feasible.

The goal of this pilot study is to assess the feasibility of randomizing hospitalized patients that are colonized with C. difficile and started on systemic antibiotics to either a probiotic, oral vancomycin, or placebo in a parallel-group 1:1:1 design. The ultimate goal is to conduct an appropriately-powered RCT to determine the optimal method for reducing C difficile infection in colonized patients.

In this study, patients will be screened for C. difficile colonization

Inclusion Criteria:

• Adult patients of 18 years of age or older identified as asymptomatic carriers of C. difficile (i.e. not meeting case definition of C. difficile infection, see below)
• Started on systemic (oral or intravenous) antibiotics for any (presumed) bacterial infection
• Patient must have vitals (heart rate, blood pressure, temperature), estimated creatinine clearance (using the Chronic Kidney Disease Epidemiology equation (CKD-Epi)) and a complete blood count available within 24 hours of enrolment

Exclusion Criteria:

• On a course of systemic antibiotics that had been started more than 72 hours ago (as current evidence suggests that the earlier probiotics are started, the more efficacious they are)

• Patient with C. difficile, i.e. presence of diarrhea (three or more loose or watery stools within 24 hours), or fevers or hypotension from C. difficile infection

• Any patients with contra-indications to probiotics or vancomycin:

  • Immunosuppressed (primary or acquired immunodeficiency, including AIDS (defined as AIDS defining condition or cluster of differentiation 4 (CD4) nadir of <200/ul), hematologic malignancies, long-term systemic corticosteroid treatment, active treatment with chemotherapeutic agents or biologicals, autoimmune diseases, nephrotic syndrome)
  • Structural heart disease (e.g. atrial septal defect, ventricular septal defect)
  • Gastroesophageal or compromised gut integrity (e.g. short gut syndrome, intestinal injury or dysfunction, inflammatory bowel diseases including current or past history of Crohn's disease and ulcerative colitis)
  • Patients on systemic aminoglycosides, ethacrynic acid, polymixin B, or colistin.
  • Prior or current hearing loss
  • Female patients with known pregnancy or who are planning to get pregnant, or who are breastfeeding
  • Patients with end-stage renal diseases defined as an estimated glomerular filtration rate of <15ml/min, or absence of a current estimated creatinine clearance
  • History of an allergic reaction to one of the study drugs, or sensitivity to milk

• Patients started on probiotics or oral vancomycin while in hospital

No individual participant data will be shared with researchers that are not directly involved in this study. Overall data will be shared in the context of peer reviewed journal publications or scientific presentations.

Blinding will be done in a double-blind fashion. The patients, their caregiver, and the investigator will be blinded to the study treatment.