A 12-year trend of antimicrobial resistance among ESKAPEEc organisms isolated from blood cultures in a large private medical diagnostic laboratory network in Malaysia (2013-2024).

BACKGROUND: ESKAPEEc blood culture isolates are important indicators of invasive bacterial disease and antimicrobial resistance (AMR). This study examined 12-year AMR trends in Malaysia. RESEARCH DESIGN AND METHODS: This retrospective laboratory-based study analyzed de-identified blood culture records from a large private diagnostic laboratory network between January 2013 and December 2024. An Antimicrobial Resistance Index (ARI) was calculated for each deduplicated patient-year isolate, and multivariable logistic regression identified factors associated with high ARI (≥0.5). RESULTS: Among 10,274 eligible isolates, Escherichia coli was most common (44.5%), followed by Klebsiella pneumoniae (20.7%) and Staphylococcus aureus (19.6%). Mean ARI increased from 0.22 in 2013 to 0.28 in 2024 (p < 0.001), while high-ARI isolates rose from 12.1% in 2020 to 22.8% in 2024. Significant increases occurred in E. coli, K. pneumoniae, and Enterobacter spp./complex. Male sex, Indian or other ethnicity, Acinetobacter baumannii, Enterococcus spp. and year 2024 were associated with high ARI. CONCLUSIONS: AMR burden increased, particularly in 2024, supporting stronger stewardship, surveillance, and updated empiric treatment guidance. Findings should be interpreted cautiously because changes in AST methods, breakpoints, test panels, referral patterns, and case mix could not be fully adjusted.