METAGENOMIC SURVEILLANCE OF ANTIMICROBIAL RESISTANCE GENES IN URBAN WASTEWATER OF PAKISTAN

Abstract

Antimicrobial resistance (AMR) has emerged as a critical global public health challenge, with urban wastewater systems increasingly recognized as major environmental reservoirs and transmission pathways for antimicrobial resistance genes (ARGs). This study employed a metagenomic approach to investigate the diversity, abundance, and distribution of ARGs in urban wastewater systems of Pakistan. A cross-sectional design was used to collect wastewater samples from municipal influent, hospital effluents, urban drainage channels, and treated effluent sites. Shotgun metagenomic sequencing was performed to characterize microbial communities and identify resistance determinants using curated ARG databases. Statistical analyses were applied to evaluate differences in ARG abundance and diversity across sampling sites. The findings revealed a high diversity of ARGs across all wastewater sources, with beta-lactam, tetracycline, and sulfonamide resistance genes being the most prevalent. Hospital effluents exhibited the highest ARG abundance, followed by municipal influent and urban drainage systems, while treated effluent showed reduced but persistent levels of resistance genes. Significant spatial variation in resistome profiles was observed across sampling sites, indicating strong anthropogenic influence on ARG distribution. Wastewater treatment processes reduced ARG loads; however, they did not eliminate them entirely, highlighting limitations in conventional treatment systems. The study concludes that urban wastewater in Pakistan serves as a significant reservoir for antimicrobial resistance genes, posing potential risks to environmental and public health. The findings underscore the need for integrated wastewater-based surveillance systems and advanced treatment technologies under a One Health framework to mitigate the spread of antimicrobial resistance