Microplastics mediated antibiotic resistance gene enrichment and transfer in environment: Different types, microplastic antibiotic resistance gene ecological island and nano-size effect

Microplastics (MPs) and antibiotic resistance genes (ARGs) pose significant environmental threats. This review examines their interaction, highlighting MPs' role in ARGs accumulation and transport. The influence of different MPs types is first outlined, then the new concept of "microplastic antibiotic resistance gene ecological island" (MPs-ARGs-EI) is introduced, the synergistic effects and molecular mechanisms are analyzed, and future prospects and control strategies are finally summarized. Specifically, it is concluded that biodegradable and aged MPs release polymeric substances and alter surface properties to enhance ARGs adhesion and diffusion. Micro-scale MPs provide an increased surface area for microbial colonization and ARGs enrichment, thereby fostering a MPs-ARGs-EI. This niche serves as both a "shelter" and a "vector" for ARGs, within which their horizontal and vertical transfer is enhanced through mobile genetic elements (MGEs), carrier effects, and other environmental stressors. This effect is exacerbated by human activities and environmental factors. Nanoplastics (NPs) may further facilitate ARGs horizontal transfer by inducing reactive oxygen species (ROS), initiating the SOS response and DNA repair mechanism, altering membrane permeability, impacting conjugative gene expression and metabolic pathways. This study provides novel insights for subsequent in-depth research and contaminant mitigation efforts.