Emergence, evolution, and global dissemination of antimicrobial resistance: A One Health review

Antimicrobial resistance (AMR) is a critical global health threat that undermines the treatment of infections and compromises medical interventions. AMR develops when microorganisms evolve mechanisms to survive antimicrobial exposure, a process accelerated by misuse and overuse of antibiotics in human medicine, agriculture, and veterinary settings. Bacterial resistance poses the greatest immediate concern, contributing to an estimated 1.27 million deaths in 2019 and nearly 5 million deaths associated with resistant infections worldwide. Without urgent intervention, Projections suggest that AMR could cause up to 10 million deaths annually by 2050, potentially surpassing cancer as a leading cause of mortality although these estimates remain subject to uncertainty. This review examines key biological mechanisms of resistance, including enzymatic degradation, target modification, efflux pumps, porin loss, and horizontal gene transfer. It highlights global hotspots and emerging resistance determinants such as NDM-1 and mcr-1, as well as antibiotic usage trends across human and animal sectors. Unlike acute pandemics such as COVID-19, AMR progresses silently but persistently, earning recognition as a "slow pandemic." Its spread involves interconnected human, animal, and environmental reservoirs, necessitating a One Health approach. The review also summarizes current global responses, including the WHO Global Action Plan, surveillance platforms such as GLASS, and ECDC, and research initiatives like CARB-X and GARDP. Despite progress, significant gaps remain in policy, surveillance, and antimicrobial stewardship, particularly in low- and middle-income countries, underscoring the urgent need for coordinated multisectoral action. However, the conclusions drawn are limited by variability in global surveillance data, differences in reporting standards, and reliance on previously published studies, which may not fully capture regional disparities.