High-throughput metagenomic profiling of functional and resistome features in estuarine microplastic microbiomes

Microplastics (MPs) are now recognized as persistent pollutants in aquatic ecosystems, providing unique surfaces for microbial colonization and acting as vectors for the spread of pathogens, antibiotic resistance, and virulence factors. Estuarine systems, due to their dynamic hydrology and proximity to anthropogenic activity, are particularly vulnerable to MP accumulation and associated microbial risks. This study presents the first comprehensive metagenomic investigation of MP-associated microbial communities across five estuaries spanning the northern and southern coastal regions of Karnataka, India. MPs were isolated, characterized, and the extracted total DNA from the MPs was subjected to high-throughput sequencing and comprehensive bioinformatic analyses. Taxonomic, functional, and resistance gene profiling were performed to evaluate microbial diversity, ecological roles, and potential public health implications. The findings revealed distinct regional differences in microbial community structure and functional potential, with evidence of clinically relevant pathogens, antibiotic resistance genes, and virulence determinants within the plastisphere. These results highlight the role of MPs as reservoirs and vectors for microbial risks in estuarine ecosystems. By linking microbial diversity of MPs with environmental and anthropogenic influences, this work provides crucial baseline data for monitoring and managing estuarine health. It also underscores the urgent need for integrated strategies to mitigate plastic pollution and its cascading ecological and public health impacts.