Sludge water: a potential pathway for the spread of antibiotic resistance and pathogenic bacteria from hospitals to the environment

Hospitals are significant sources of antibiotic resistance genes (ARGs) and antimicrobial resistance (AMR), which accumulate in activated sludge. This study explores the behavior of ARGs during sludge concentration and dewatering. Results show a strong correlation between ARGs in sludge water and hospital wastewater, with subtypes like arlR, efpA, and tetR showing higher abundance in sludge water. ARGs are primarily transmitted through coexisting mobile genetic elements, suggesting sludge water is a critical route for ARG release, posing potential threats to public health and ecological safety.