Economic Barriers to Antimicrobial Susceptibility Testing as a Structural Contributor to Antimicrobial Resistance in Low- and Middle-Income Countries: A Narrative Review.

BACKGROUND

Bacterial antimicrobial resistance (AMR) was directly responsible for an estimated 1.27 million deaths in 2019, with the burden. Antimicrobial susceptibility testing (AST) is essential for guiding targeted therapy and stewardship, yet the specific economic mechanisms that prevent its scale-up in low-resource settings remain poorly understood and inadequately addressed in policy.

METHODS

A narrative review was conducted following SANRA guidelines and PRISMA transparency principles. PubMed/MEDLINE, Scopus, and Google Scholar were searched (01 January 2026-30 April 2026) using Boolean combinations of terms across three domains: AST and diagnostics; economic and health-system barriers; and AMR and stewardship. Studies published 2019-2026 addressing economic barriers to AST, prescribing behaviour, resistance patterns, or financing strategies in LMICs were eligible. Evidence was synthesized thematically.

FINDINGS: Economic barriers to AST operate at three levels: patient-level out-of-pocket costs and transport; laboratory-level infrastructure deficits, reagent shortages, and workforce gaps; and health-system-level underinvestment and donor dependency. These barriers sustain broad-spectrum empirical prescribing, amplify selection pressure, and drive the emergence of methicillin-resistant Staphylococcus aureus (MRSA), extended-spectrum β-lactamase (ESBL)-producing Enterobacterales, and carbapenem-resistant organisms. Consequences include treatment failure, catastrophic household expenditure, and threats to universal health coverage. Effective responses require subsidized diagnostics, insurance coverage for microbiology services, tiered laboratory strengthening, and integration of diagnostic stewardship with antimicrobial stewardship.

CONCLUSION

Economic barriers to AST are a structural, multi-level contributor to AMR in LMICs. Sustainable AMR control requires financed national action plans that explicitly fund accessible, quality-assured AST alongside prescribing reform.