Microplastics: Hidden drivers of antimicrobial resistance in aquatic systems

Microplastics (MPs) in aquatic ecosystems readily promote biofilm formation, creating the plastisphere, a dynamic interface that interacts with environmental pollutants and acts as a reservoir for microorganisms. Recent studies emphasize the plastisphere's contribution to the spread of pathogens, antibiotic-resistant genes (ARGs), and antimicrobial resistance (AMR) within aquatic organisms and across diverse environments, a phenomenon collectively called the 'Plastiome'. Although the prevalence and effects of the plastisphere have been studied extensively, a systematic synthesis of updated insights into the behavior of the plastiome is urgently needed. This review explores the development and behavior of plastics, focusing on its interactions with ARGs and pathogens within aquatic ecosystems. Microplastics selectively enrich ARGs and pathogenic microorganisms, fostering unique microbial communities distinct from those in surrounding waters. The plastiome facilitates horizontal ARG propagation, increasing the quantity of antibiotic-resistant pathogens and presenting substantial risks to the hydrosphere and public health. Additionally, key research opportunities are identified and strategies are recommended to advance our understanding of plastiome-driven antibiotic resistance in aquatic environments.