Implementation and Early Outcomes of an Antimicrobial Stewardship Program in South Korea

Background: Antimicrobial stewardship programs (ASPs) are essential for promoting the rational use of antibiotics and combating resistance. In South Korea, implementation has recently accelerated, but real-world data on short-term program performance remain limited. This study evaluated the early outcomes of a newly launched ASP at a tertiary hospital. Methods: This retrospective, single-center study analyzed ASP activity from January to April 2025. Interventions included prospective audit and feedback for restricted antibiotics and recommendations for prolonged antibiotic prescriptions (≥14 days). The primary outcome was the monthly rejection rate of restricted antibiotics. Secondary outcomes included days of therapy (DOT) for restricted antibiotics and the acceptance rate of interventions for prolonged prescriptions. Results: The monthly rejection rate of restricted antibiotics remained stable between 3.65% and 4.68%. Although the DOT values did not show statistical significance, they demonstrated a moderate inverse correlation with the rejection rate (Pearson's r = -0.868, p = 0.132). Among 826 prolonged prescriptions, 513 (62.1%) received ASP intervention. Acceptance of recommendations increased over time, from 67.0% in January to 82.5% in April. Interventions were primarily based on insufficient evidence of infection or inappropriate antibiotic selection. Conclusions: The newly implemented ASP demonstrated feasibility and early impact in improving antibiotic oversight. Despite the short observation period, the findings suggest a positive influence on prescribing practices. Longer-term studies are needed to evaluate sustained clinical outcomes and broader applicability in diverse healthcare settings.