Antibiotic contamination and antimicrobial resistance dynamics in the urban sewage microbiome in India

This study demonstrates that sewage is a major reservoir and transmission hub for antimicrobial resistance in India. Analysis of sewage samples from six states revealed widespread presence of antibiotics from multiple drug classes, high microbial diversity, and extensive antimicrobial resistance gene (ARG) richness. Metagenomic and isolate-based analyses identified numerous ARGs linked to mobile genetic elements, predominantly in multidrug-resistant pathogens, with strong genetic similarity between sewage-derived strains and clinical isolates. Together, the findings show that sewage environments promote genetic exchange and the evolution of AMR, and highlight the value of low-cost, dipstick-based ARG detection as a practical surveillance tool in low-resource settings.