To tackle antimicrobial resistance (AMR), i.e., one of the top 10 global health threats, antimicrobial stewardship (AMS) programs, i.e., coherent sets of actions promoting responsible use of antimicrobials, have been developed. Despite growing evidence about their effectiveness, their implementation remains suboptimal. Qualifying as complex interventions, these programs are prone to interactions with context, potentially compromising their successful transfer to other settings. AMR remains critical in French nursing homes (NHs). AMS programs have proven effective in reducing antimicrobial resistance in hospitals and in NHs. However, the evidence is inconsistent across studies in NHs and mostly based on North American and North European AMS programs and studies, raising concerns about transferability that might occur while implementing such AMS programs in French NHs. For instance, health systems and NH funding and organization vary considerably across countries, resulting in potential key determinants driving antibiotic use in such facilities in some countries that might remain untargeted by AMS programs developed in other countries. In addition, inconsistent effectiveness of AMS programs in NHs might also result from implementation issues, raising concerns about the strategies used to implement such programs. Based on extensive logic models linking psychosocial and organizational determinants driving antibiotic use in NHs of diverse countries, we developed and pilot-tested a customizable AMS program (i.e., the ORANEAT program) suited to French NHs, including three major components: (i) a contextual diagnostic regarding AMS in the targeted NH; (ii) based on the results of the contextual diagnostic, a bundle of tools selected from an AMS-toolkit including actions and tools suited to French NH setting; and (iii) implementation support relying on French structures involved in tackling AMR (i.e., CRAtb and CPias).

This study aims to assess the effectiveness, the sustainability, the implementation, and the transferability of the ORANEAT program in French NHs, using a mixed-method approach (quantitative and qualitative data). A cluster randomized controlled trial with two arms (ORANEAT program vs. no specific intervention) will be conducted; the cluster being the NH. The primary outcome to measure the effectiveness is total antibiotic use expressed in defined daily doses/1000 resident-days/month.

Nursing homes

Inclusion criteria:

• Nursing home located in one of the geographical areas participating in the study in two French regions (i.e., geographical areas covered by experts in antibiotic stewardship and/or in infection prevention and control who agreed to participate in the study)

Exclusion criteria:

• Nursing home with a pharmacy for internal use
• Participation to the pilot study
• Data from the Health Insurance reimbursement database (Système national des données de santé) not available on the study period
• Refusal of the nursing director to participate in the study (for Arm 1 only)

Residents (Outcomes 1 to 4 and outcome 12)

Inclusion criteria:

• Resident aged 18 or more who had lived in one of the participating nursing homes during the study period.

Exclusion criteria:

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Healthcare professionals (Outcomes 11, 13 and 15)

Inclusion criteria:

• Healthcare professionals aged 18 or more working in one of the participating nursing homes from Arm 1 (including healthcare professionals who provide services to or collaborate with the nursing home even if they are not on-site, e.g., private general practitioners, community pharmacists, microbiologists, and professionals responsible for the implementation support).

Exclusion criteria:

• Refusal to complete the self-administered questionnaires or to participate in qualitative investigations.

IPD Sharing Plan Description: N/A

The statisticians responsible for analyzing data on antibiotic use (using data from the Health Insurance reimbursement database, Système national des données de santé)