Investigating the impact of landfill age and season on the occurrence and dissemination of antibiotic resistance genes in leachate and the underlying mechanisms using metagenomics.

This article focuses on the occurrence, seasonal dynamics, and influencing factors of antibiotic resistance genes (ARGs) in landfill leachate from a semi-arid region in Hohhot, Inner Mongolia, China. Using comprehensive metagenomic analysis across landfills of different ages (5, 10, and 20 years) and seasons, the study found that landfill age primarily affected tetracycline- and glycopeptide-ARG abundances, while seasonal variations mainly influenced glycopeptide- and multidrug-ARGs. The predominant ARG-hosting pathogens identified were Pseudomonas aeruginosa and P. fluorescens, with higher prevalence in spring and winter. Importantly, the research revealed a novel mechanism linking landfill age to ARG dissemination through modulation of microbial carbohydrate and nitrogen metabolic pathways, providing a theoretical framework for managing ARG spread in semi-arid landfill environments.