Urbanization-driven pollution enhances plasmidome diversity and abundance in tropical river watershed bacterial communities, revealing contrasting dynamics with chromosomal diversity across water and sediment samples

In this study, we analyzed the plasmidome of a highly polluted tropical river significantly impacted by urbanization. We utilized metagenomic sequences from sediment and water column samples collected along a pollution gradient in a Costa Rican River watershed, and we also determined the relative abundance of antibiotic resistance genes (ARGs) in both water and sediment samples. Additionally, we developed a novel bioinformatics platform to improve plasmid analysis from environmental DNA. By focusing on plasmids carrying ARGs, we hypothesized that urban pollution increases plasmidome richness and diversity.