BACKGROUND: The Centres for Antimicrobial Optimization Network Brazil aims to implement an antimicrobial stewardship program in Brazilian municipality. This study explores barriers and enablers to its implementation, through understanding the context and beliefs regarding antimicrobial use in this environment. METHODS: The study occurred in 12 primary health care units, where a mixed-method study was conducted. A total of 208 out of 450 health care workers completed a Theoretical Domain Framework-based survey, and 16 patients and 12 health workers were interviewed. Survey results were compared by professional category
interviews were analyzed using Critical Discourse Analysis. RESULTS: Professionals with higher education scored higher across most domains. In the "Optimism" domain, these professionals scored ≥6.0, while others scored ≤5.0. Similar patterns were observed in the domains "Knowledge" (≥6.0 vs ≤5.5), "Social/professional role and identity" (≥6.36 vs ≤5.79), and "Intentions" (≥6.0 vs ≤5.0). Qualitative data highlighted breaks in the continuity of care and gaps in patient knowledge about antimicrobial use. Key barriers included disparities in training, physician-centered decision-making, and patient knowledge gaps. Enablers included health care workers' willingness to learn and home caregivers' understanding of patient conditions. CONCLUSIONS: The implementation of the antimicrobial stewardship program depends on addressing training disparities and leveraging health care workers' willingness to learn.