Trends in Antimicrobial Resistance among Bloodstream Isolates in Korea and Japan during 2016–2023: A Comparative Analysis of Kor-GLASS and JANIS Data

Background: Antimicrobial resistance (AMR) poses a critical challenge to human health.Despite their geographical proximity, Korea and Japan have implemented distinct national AMR surveillance strategies and infection control policies.This study aimed to compare recent trends in AMR among major bloodstream bacterial pathogens in these two countries.Methods: Nationwide antimicrobial susceptibility data from the Korea Global Antimicrobial Resistance Surveillance System and Japan Nosocomial Infections Surveillance between 2016 and 2023 were analyzed.To ensure comparability, the analyses were restricted to bloodstream isolates of major Gram-positive and Gram-negative pathogens, including Staphylococcus aureus, Enterococcus spp., Escherichia coli, and Klebsiella pneumoniae.Temporal trends in the resistance rates were evaluated between Korea and Japan.Results: Resistance rates were generally higher in Korea than in Japan across most evaluated pathogen-antimicrobial combinations.Although the prevalence of methicillin-resistant S. aureus declined in both countries, substantial disparities persisted between vancomycin-resistant E. faecium (VREfm) and carbapenem-resistant organisms, particularly K. pneumoniae and Acinetobacter spp.Notably, the prevalence of VREfm exceeded 30% in Korea but remained at < 1% in Japan; the prevalence of carbapenem-resistant Acinetobacter spp. was ≥ 69% in Korea, but < 2.5% in Japan.Conclusions: The divergent AMR trajectories may be associated with differences in healthcare delivery structures, infection control measures, antibiotic consumption, circulating AMR strains, and antimicrobial stewardship implementation.The endemicity of VREfm and carbapenem-resistant organisms in Korea underscores the difficulty in reversing established resistance and highlights the importance of proactive early interventions.These findings emphasize the need for tailored context-specific AMR control strategies that account for the national healthcare infrastructure.