Impact of Antimicrobial Stewardship in a Rural Veterinary Clinic Network in Brazil

Thesis Abstract

The emergence of antimicrobial resistance in animal populations and the consequent risk to public health necessitate effective antimicrobial stewardship (AMS) within veterinary practice, particularly in resource-constrained rural clinic networks where stewardship practices are heterogeneous and progress is uneven. This study addresses the problem by examining how the implementation of an antimicrobial stewardship program (ASP) influences prescribing behaviors, antimicrobial usage patterns, and clinical outcomes across a network of rural veterinary clinics in Brazil. The aim is to evaluate the impact of a structured AMS intervention on prescribing appropriateness, antibiotic consumption, and treatment outcomes, and to identify facilitators and barriers to sustained implementation in a real-world setting. Specific objectives include (i) quantifying changes in antimicrobial prescribing indicators (defined daily doses per 100 consultations, proportion of first-line versus broad-spectrum agents) before and after ASP deployment; (ii) assessing adherence to evidence-based guidelines for common bovine, porcine, and small animal infections; (iii) evaluating changes in clinical outcomes such as cure rates, recurrence, and adverse events; (iv) exploring stakeholder perceptions of the ASP’s acceptability, feasibility, and sustainability; and (v) developing a context-specific conceptual model linking program components to observed outcomes. A mixed-methods design will be employed, integrating quantitative and qualitative strands to generate comprehensive insights. The population comprises all rural clinics within the network, with a retrospective pre-intervention period (12 months) and a prospective post-intervention period (12 months). A total of 28 clinics will be included, with all prescriptions for systemic antimicrobials recorded during the study windows. Quantitative data will be collected from veterinary prescription records, pharmacy inventories, and animal health records, capturing variables such as antimicrobial class, indication, dosage, duration, and outcome, alongside clinic-level metrics (client volume, case mix). Primary instruments include an adapted AMS audit tool aligned with Brazilian national guidelines and the WHO Essential Medicines List. Regression analyses, including interrupted time-series (ITS) and multilevel mixed-effects models, will assess changes in prescribing indicators and outcomes, controlling for confounders such as seasonality and clinic size. Secondary analyses will apply segmented regression to ITS data to detect immediate and gradual effects of the intervention. Additionally, propensity score matching will be used to compare outcomes where appropriate. Qualitative data will be generated through semi-structured interviews and focus groups with veterinarians, veterinary technicians, and clinic managers (n ? 40 participants) and analyzed using thematic analysis guided by Braun and Clarke’s framework. Triangulation with quantitative findings will elucidate mechanisms of change, contextual factors, and perceived barriers or enablers to adherence with guidelines. Theoretical framing will draw on the Theory of Planned Behavior to interpret prescribing intentions and behavior, and the Diffusion of Innovations theory to explain adoption patterns across clinics, with explicit integration of these constructs into a conceptual model. Expected findings include a significant reduction in defined daily doses per 100 consultations and a higher proportion of first-line agents prescribed for common indications, coupled with improved guideline concordance and stable or improved clinical outcomes. The study anticipates heterogeneity in intervention impact driven by clinic leadership, access to diagnostics, and continued education, highlighting critical factors for successful scale-up. The contribution to knowledge lies in providing empirical, context-specific evidence on AMS effectiveness within rural veterinary networks in a middle-income country, detailing implementation processes, fidelity, and sustainability challenges, and offering a transferable framework for AMS deployment in similar settings. The recommendations will emphasize policy alignment, ongoing training, integration of decision-support tools, monitoring infrastructures, and patient safety considerations, with practical guidance for achieving durable reductions in inappropriate antimicrobial use without compromising animal welfare. The study concludes that well-structured AMS interventions can meaningfully improve antimicrobial stewardship in rural Brazilian veterinary networks, contingent upon robust monitoring, stakeholder engagement, and adaptable implementation strategies informed by local practice realities.