Antimicrobial resistance in Ecuador, 2000-2024: a systematic review within a One Health framework.

Antimicrobial resistance (AMR) is a major global public health threat, particularly in low- and middle-income countries. In Ecuador, AMR research has expanded during the last two decades, but evidence remains fragmented and largely restricted to the human health sector. We systematically reviewed studies reporting laboratory-confirmed bacterial resistance in Ecuador between 2000 and 2024, including evidence from human, animal, food, and environmental sources. Eighty studies met the inclusion criteria. Most were hospital-based and conducted in urban areas, with limited evidence from rural, Amazonian, and insular regions. Gram-negative bacteria accounted for the greatest resistance burden, particularly Escherichia coli (56.6%), Klebsiella pneumoniae, Salmonella spp. (22.3%), the Acinetobacter baumannii complex, and Pseudomonas aeruginosa, together with resistant Staphylococcus aureus and Mycobacterium tuberculosis. Resistance to beta-lactams and fluoroquinolones predominated, whereas carbapenem resistance was especially notable among WHO priority pathogens. Evidence from animal, food, and environmental sectors was scarce and heterogeneous, and molecular characterization was inconsistently reported. These findings highlight important surveillance gaps beyond hospital settings and underscore the need for integrated multisectoral surveillance to strengthen public health policy, antimicrobial stewardship, and AMR prevention in Ecuador.