Insights into antibiotic resistomes from metagenome-assembled genomes and gene catalogs of soil microbiota across environments

Antibiotic resistance poses a significant global health threat, and soil is recognized as a critical reservoir for antibiotic resistance genes (ARGs). To investigate soil microorganisms in the areas where both humans and common domestic animals (such as pigs and chickens) are present and active. In this study, we employed metagenomic sequencing to investigate the soil resistome across four Chinese provinces-Yunnan, Guizhou, Sichuan, and Jiangsu. From 111 soil samples, we generated metagenome-assembled genomes (MAGs) and gene catalogs to analyze microbial community composition, ARG distribution, and mobile genetic elements (MGEs). Our results revealed notable regional differences in microbial communities and ARG profiles. Pseudomonadota and Actinomycetota were the dominant phyla across samples, and ARG abundance was significantly higher in Sichuan, Yunnan, and Jiangsu compared to Guizhou. We also identified microbial taxa likely serving as ARG vectors, suggesting potential for horizontal gene transfer. Functional annotation indicated that metabolic functions, particularly carbohydrate and amino acid metabolism, were predominant, which may be associated with the composition of organic matter in the soil environment. Multidrug resistance genes are widespread in soil microbial communities and may spread through food chains or soil-water-plant systems, posing potential ecological and public health risks. MGEs showed significant regional variation and play a key role in the horizontal spread of ARGs. Together, these findings provide new insights into the soil antibiotic resistome and offer a foundation for developing targeted strategies to manage environmental antibiotic resistance.