Systematic review of wild birds as reservoirs of antimicrobial resistance: Implications for roof-harvested rainwater safety

This review shows that wild birds—especially urban-adapted species like gulls and pigeons—can act as important reservoirs and spreaders of antimicrobial resistance (AMR). These birds frequently carry clinically relevant resistant bacteria, including carbapenem-resistant Enterobacterales (CRE), multidrug-resistant and ESBL-producing E. coli, MRSA, and resistance genes such as colistin and MLS. Urban foraging in landfills, sewage, and waste sites increases their exposure and amplifies their role in environmental AMR dissemination. A key concern is roof-harvested rainwater, increasingly used due to climate change and water scarcity, which can be contaminated by bird droppings yet remains largely unregulated. The review underscores the need for better monitoring, targeted research, and risk management to reduce AMR transmission from birds to humans via environmental pathways.