Metagenomic profiling of antimicrobial resistance in wastewater from metropolitan cities of India

Wastewater-based surveillance has emerged as a powerful tool for monitoring microbial diversity, antimicrobial resistance genes (ARGs) and mobile genetic elements (MGEs). In this study, wastewater samples collected from March 2022 to March 2024 from 19 locations in four metropolitan cities of India were profiled using shotgun metagenomics. Taxonomic abundance and beta diversity analyses revealed significant differences in microbial community compositions, with city-specific clustering; suggesting distinct local environmental influences. However, such distinct clusters were not evident with the ARGs. A high proportion of potentially novel metagenome-assembled genomes (MAGs) (53-70%) were identified on reconstructing the microbial genomes from the metagenomic data. ARGs conferring resistance to antibiotics such as tetracyclines and beta-lactams showed higher association with MGEs in contrast to macrolide resistance genes. Microbial co-occurrence network analysis revealed a city-specific structure and higher contribution of ARGs from specific communities of microbes. These findings underscore the complex interplay between microbial diversity, ARG dissemination, and MGEs in wastewater environments, emphasizing the need for continued surveillance, for designing appropriate mitigation strategies towards curbing the spread of antimicrobial resistance.