Environmental drivers of high-risk antibiotic resistance genes propagation in the plastisphere unveiled by...

The plastisphere serves as an expanding reservoir and dissemination vector for antibiotic resistance genes (ARGs), yet the environmental driving factors on high-risk ARG dynamics within this niche remain poorly understood. Herein, a multi-effect meta-analysis was conducted to quantify the influence of environmental factors on high-risk ARGs within the plastisphere. Relative to ambient waters, significant enrichment was observed for ARGs targeting macrolide (ermC, +114.47%), quinolone (aac(6')-Ib, + 89.62%), sulfonamide (sul1, +57.16%), quinolone (qnrS, +33.01%), and class I integrons (intI1, +48.61%). Among microplastics, polyethylene and polypropylene exhibited selective ARGs enrichment, exceeding concentration levels of ambient waters by 80.63% and 71.89%, respectively. Mantel and binning analyses quantified contributions of 13 environmental factors to 9 ARG genotypes and intI1. Additionally, molecular fingerprints (n = 92) obtained via RDKit revealed the contributions of microplastics' physicochemical properties. Independent explainable machine learning (ML) models developed using the H₂O-AutoML platform for sul1 and intI1 achieved high predictive accuracy. Shapley Additive Explanations (SHAP) analysis identified near-equal associations between intI1 risk and aquatic parameters (49.3%) versus microplastics (MPs) characteristics (50.3%), whereas sul1 risk was predominantly influenced by MPs (91.2%). This study enhances the understanding of the dynamics of ARGs in the plastic cycle and provides a methodological reference for the subsequent development of a predictive framework for rapid, large-scale monitoring of high-risk ARGs in aquatic environments.