A composite health system capacity index and antimicrobial resistance among bloodstream infections: A multi-country ecological analysis

Background/Aim: Antimicrobial resistance (AMR) varies substantially across countries and is influenced by broader health-system and socioeconomic conditions. However, the extent to which publicly available structural indicators can summarise national vulnerability to bloodstream AMR remains incompletely characterised. This study aimed to develop a public-data composite Health System Capacity Index (HSCI) and examine its ecological association with selected bloodstream AMR phenotypes.Methods: A multi-country ecological analysis was conducted using harmonised public data from the World Health Organization (WHO) Global Antimicrobial Resistance and Use Surveillance System (GLASS), the WHO Tracking AMR Country Self-Assessment Survey (TrACSS), the European Centre for Disease Prevention and Control (ECDC) and global structural indicators. The HSCI was derived from six complete-case indicators capturing infection prevention and control (IPC) capacity, AMR surveillance, antimicrobial use monitoring, hospital bed capacity, gross domestic product per capita and Human Development Index. Higher HSCI values indicated greater structural vulnerability. Outcomes included bloodstream Escherichia coli third-generation cephalosporin resistance, methicillin-resistant Staphylococcus aureus (MRSA) resistance and European healthcare-associated infection (HAI) prevalence. Linear regression and clustering analyses were performed.Results: Among 102 countries, analytic samples included 82 for E coli, 84 for MRSA and 29 for HAI prevalence. Higher HSCI values were associated with higher E coli third-generation cephalosporin resistance (β = 0.706; p < 0.001; R² = 0.499) and MRSA resistance (β = 0.458; p < 0.001; R² = 0.210), but not with European HAI prevalence (p = 0.301). Domain-specific analyses indicated that development and economic indicators explained more variance than infection prevention and control (IPC)-specific indicators.Conclusion: Publicly available structural indicators can be combined into a reproducible composite index associated with selected national bloodstream AMR phenotypes. The findings should be interpreted as ecological associations reflecting broader health-system capacity rather than direct evidence of IPC-specific performance or causality.