The rise of antimicrobial resistance (AMR) poses a critical global health challenge. Bloodstream infections contribute significantly to global morbidity and mortality, exacerbated in low- and middle-income countries (LMICs) by insufficient healthcare access and quality. Recognising this, the United Nations has prioritised combating AMR and bloodstream infections within its Sustainable Development Goals, aiming to bolster LMICs' healthcare capacities by 2050. Despite their significance, studies on the disease burden in LMICs remain limited, and there is an urgent need to update in-hospital AMR management guidelines. My PhD project focused on enhancing the epidemiological understanding of AMR-related bloodstream infections in LMICs, with a particular case study in Chile utilising patient-level data. Starting with a comprehensive global analysis of AMR, I examined its association with various factors through a One Health lens. A meta-analysis was performed to quantify the disease's burden in terms of mortality, hospital stay lengths, ICU admissions, and economic impacts. In Chile, an epidemiological analysis of in-hospital AMR trends over time was conducted, identifying key pathogens and risk factors relevant across different settings and regions. By analysing patient-level data on bloodstream infections, the additional health and economic burdens posed by AMR from a national cohort of1,218 patients with bloodstream infections was estimated. Through mathematical modelling, I assessed potential intervention strategies, reviewing their financial implications and projected their cost-effectiveness. These findings culminated in recommendations for improving infection control practices. Focusing on Chile provided a precedent for healthcare improvements in regions where data remains scarce and AMR a growing threat.