Values and trade-offs in responsible antibiotic behaviour and sustainable access: protocol for a comparative mixed-methods empirical ethics study in Sweden, Italy, and Bulgaria

Background Antibiotic resistance arises through biological evolution but is also shaped by behavioural, sociocultural, and institutional factors. Promoting responsible antibiotic behaviour requires understanding how members of the public and relevant stakeholders perceive antibiotic use, stewardship, access, and responsibility, and the values and trade-offs that shape their decisions. This study aims to investigate these factors across three national contexts and to develop context-sensitive recommendations and a methodological framework for future research. Methods This protocol describes an ongoing comparative mixed-methods empirical ethics study conducted in Sweden, Italy, and Bulgaria from May 2025 to April 2028. The study comprises three connected components: semi-structured online interviews with 16–20 participants from four stakeholder groups in each country; a general-population survey incorporating a discrete choice experiment, with a minimum of 350 respondents per country; and iterative normative analysis using reflective equilibrium. The 3D Value Framework informs the interviews, which examine stakeholders’ reasoning about sustainable antibiotic access, stewardship, responsibility, and preparedness. Interview findings, relevant literature, and previous research will inform the survey attributes and scenarios. The survey will examine public preferences and trade-offs concerning antibiotic treatment, responsible behaviour, and sustainable access, alongside antibiotic knowledge, trust, prosociality, biospherism, gender-related perspectives, social norms, and values. The empirical findings will be interpreted in relation to ethical theories of justice and personal and collective responsibility. A One Health perspective informs the overall study. Discussion By bringing stakeholder reasoning and public preferences into dialogue with normative analysis, the study will examine how responsibility for preserving antibiotic effectiveness and sustainable access should be understood and distributed between individuals and institutional actors. It will also address the ethical implications of trade-offs between present and future access and the distribution of associated benefits and burdens. This empirical ethics approach is expected to support a context-sensitive account of justice and responsibility and to inform ethically justified antibiotic stewardship, policy, and communication. Clinical trial number Not applicable.