Type- and Treatment Duration-Dependent Efficacy of Metal–Organic Frameworks for Combating Antibiotic Resistance Genes in Real Wastewater

Antibiotic resistance genes (ARGs) in aquatic environments pose enormous health risks. Metal-organic frameworks (MOFs) show promise in mitigating antibiotic resistance by diminishing antibiotic selection pressures and killing specific antibiotic-resistant bacteria. However, their effectiveness in reducing ARGs in real wastewater containing intact microbial communities remains unclear. This study investigated the effects of two typical MOFs, NH₂-MIL-53 (Al) and NH₂-UiO-66 (Zr), on ARG abundance dynamics in collected manure-contaminated wastewater. Without MOFs, ARGs naturally declined after 15 days, with a slight initial rise. The influence of MOFs on ARG abundances depends on their types and treatment time. NH₂-UiO-66 (Zr) reduced ARG abundances by 13.94-29.63% after 5 days treatment, whereas NH₂-MIL-53 (Al) exhibited limited efficacy. Both MOFs impeded natural ARG attenuation after 15 days, reducing attenuation efficiency by 13.06-126.37%. MOFs modified potential bacterial host abundances of ARGs (e.g., DMER64, Pigmentiphaga, and Aminobacter), likely by alleviating hydrogen competition among bacteria and inducing degradative bacterial proliferation by spontaneous degradation products, which was further supported by microbial function analysis. Additionally, MOFs stimulated antibiotic biosynthesis, potentially increasing corresponding ARG abundances. NH₂-MIL-53 (Al) also enhanced ARG horizontal transfer, aligning with abundance trends. This study highlights limited efficiencies of MOFs for ARG contamination control in real wastewater, providing insights for future material development.