Role of Trace Elements in Antimicrobial Resistance Dynamics

Antimicrobial resistance (AMR) has emerged as a major threat to global public health and food safety, particularly in agricultural systems where non-antibiotic agents such as metals derived from fertilizers, pesticides, and livestock waste accumulate through intensive farming practices. As trace elements, these non-degradable pollutants, including specific metals (copper, zinc), metalloids (arsenic), and nonmetallic components like nanoparticles (NPs) from agrochemicals, exert long-term selective pressure on soil and aquatic microbiomes in farmland and aquaculture environments. We review how such pressures alter microbial community composition and enhance horizontal gene transfer (HGT) of antibiotic resistance genes (ARGs) through conjugation, transformation, transduction, and membrane vesicle transport. Critically, sub-lethal concentrations of engineered nanoparticles (NPs), increasingly used as antimicrobial agents in agriculture, may paradoxically promote nano-resistance and co-select for AMR. By synthesizing mechanisms driving AMR spread under these stressors, this work highlights the urgency of re-evaluating agricultural pollution management strategies such as optimizing metal thresholds in irrigation water and regulating nano-agrochemicals to mitigate resistance evolution. Our analysis bridges the gap between environmental AMR drivers and sustainable agricultural practices, providing actionable insights for policymakers and stakeholders.