Background: There is an urgent need to develop new strategies to prevent Clostridium difficile infections (CDI). A recent study suggests that a novel infection control bundle (IC bundle) can lead to a significant decrease in the incidence of CDI in acute-care hospitals. This IC bundle consists in screening patients for C. difficile carriage upon their admission combined with implementation of isolation precautions for carriers. Further investigations are required to confirm these findings.

Objective: To evaluate the feasibility of implementing a multicenter interventional study to further to investigate the efficacy of this IC bundle.

Methods: Prospective, cluster randomized feasibility trial of 2 infection control strategies (a "standard" and an "experimental" strategy) to reduce transmission of C. difficile among patients in 20 medical wards in 5 acute-care facilities in Quebec. Wards will be randomized (1:1) to one of the 2 interventions. Each intervention will be applied to all patients present on selected wards. The study will be divided into (1) a 3-month baseline period; (2) a 2-week randomization and implementation period; and (3) an 8-week intervention period.

Intervention: The "experimental strategy" includes the components of the above-mentioned IC bundle. The "standard strategy" will not implement the IC bundle.

Outcomes: As a feasibility study, process evaluation will form the primary and secondary outcomes. These outcomes will allow to determine whether a future main trial is possible and desirable.

Hypothesis: We hypothesize that the intervention will be implementable across the study wards.

Significance: This study is essential to plan a subsequent definitive trial to determine whether the IC bundle can prevent CDI.

C. difficile is a gram-negative anaerobic bacteria that causes C. difficile infection (CDI), a disease involving the colon and causing symptoms ranging from mild diarrhea to fulminant colitis. C. difficile can spread from patients to patients in acute-care hospitals. Transmission is believed to occur mainly from patients with active disease, but patients who carry the bacteria without any symptom (called C. difficile carriers) can also transmit the bacteria to other patients.

Preliminary evidence that suggest that detecting C. difficile carriers to place them under isolation precautions can lead to a decrease in the incidence of CDI. In order to investigate this question, large-scale clinical trials will be ultimately required. In order to plan such large-scale study, there is a need to perform a preliminary feasibility trial. The current study will assess the feasibility, acceptability and logistical considerations of implementing a multicenter intervention consisting of the detection and isolation of C. difficile carriers on hospital admission, in order to guide the design of a definitive trial. This objective is essential considering the paucity of published data on this topic.

Because both strategies will be applied at the ward level, the inclusion and exclusion criteria apply to wards, not to individual patients. All patients and healthcare workers on each ward will be assigned to the intervention.

Inclusion criteria:

Clusters (i.e. wards) are eligible to take part in the study if they meet the following criteria:

• Adult medical or surgical wards;
• Patient volume: ≥5 admissions/month and ≥600 patient days/month in 2015;
• Incidence rate of CDI of ≥5/10 000 patient-days based during in 2014-2015;
• Commitment by the hospital administration to have the hospital undergo randomization for the trial (Willingness to be randomized in either arm of the study);
• Institutional agreement to screen all eligible new admissions for CD carriers and isolate CD carriers in accordance with the study protocol;
• Signed protocol signature page indicating willingness to enroll the ward in the study from the director of the hospital;
• Capacity to implement protocol (screening, isolation, respect of contact precautions);
• Capacity to screen patients by PCR with a turnaround time of <24 h;
• Participation in the Quebec CDI surveillance program (SPIN-CD);
• No existing protocol to detect and isolate CD carriers (isolation of CDI patients with resolved diarrhea allowed);
• Stable use of infection-prevention initiatives and products during the baseline period;
• Agreement to refrain from adopting new initiatives that would conflict with the trial.

Exclusion criteria:

• Wards planning to enroll subjects in other studies that aim to eradicate or prevent colonization with C. difficile or management strategies that have CD carriers or CDI as an outcome.
• Gender-biased wards (gynecology/ obstetrics, urology).