Microplastics as Potential Vectors of Antimicrobial Resistance in Hospital Wastewater: From Resistome Detection to Evolutionary Risk

Antimicrobial resistance (AMR) in hospital wastewater develops within a highly heterogeneous environment. Along with resistant bacteria and antimicrobial resistance genes, these waste streams can contain mobile genetic elements, residual antimicrobials, disinfectants, heavy metals, and other chemical pollutants. The presence of microplastics adds another potentially important component to this system. Their surfaces can be colonized by microorganisms and support biofilm development, while the particles may also retain extracellular DNA and interact with chemicals present in the surrounding wastewater. These properties suggest that microplastics could alter the local conditions under which resistant microorganisms persist and resistance determinants are exchanged.Studies indicate that microplastic-associated biofilms can harbour antimicrobial resistance genes, virulence-associated determinants, mobile genetic elements, and prophage-associated sequences. Microplastic-associated biofilms may increase opportunities for horizontal gene transfer by promoting cell proximity and retention of extracellular genetic material.