China’s landmark National Action Plan to Contain Antimicrobial Resistance (2016–2020) may have left a measurable signature in the country’s soils, according to a new National Science Review study.
Led by Tong Zhang (The University of Hong Kong), with collaborators from Zhejiang University, the team analyzed 2,243 soil metagenomes collected across China from 2009 to 2022, alongside 2,556 global soil metagenomes.
Researchers catalogued 2,043 antibiotic resistance gene (ARG) subtypes and 108 high-risk ARG subtypes across land uses. Croplands emerged as the hotspot, showing the highest relative abundance, diversity, and potential risk of ARGs, including clinically significant genes such as blaNDM and mcr.
A key finding surfaced when samples collected before and after 2016 were compared, aligning with policy rollout. In cropland soils, overall ARG abundance fell by 52.6% and high-risk ARG abundance dropped by 77.0% after 2016.
More than 70% of ARG types declined during this period, including resistance markers linked to beta-lactams, quinolones, tetracyclines, and macrolide-lincosamide-streptogramin antibiotics. The timing suggests that large-scale AMR interventions can extend beyond hospitals into environmental resistomes.
The study also linked soil ARG trajectories with national patterns in clinical antibiotic resistance, human antimicrobial use density, and veterinary antimicrobial consumption. While these relationships are associative rather than proof of direct causality, they strengthen the case for cross-sector spillover effects.
To probe environmental drivers, the team sampled cropland soils in 2021 and measured 437 chemical contaminants, from antibiotics and metals to pesticides and non-antibiotic pharmaceuticals. Pollutant concentrations accounted for roughly 29.0–31.7% of residual total ARG variation, while agricultural activities explained about 23.9–25.4%.
Importantly, tetracycline resistance genes frequently co-occurred with metal resistance genes for multiple metals, indicating possible co-selection pressures in the field.
Finally, global comparisons revealed that cropland “core” ARGs show stronger connectivity across regions than natural land uses, with greater similarity suggesting convergent resistome profiles under shared agricultural pressures—supporting the need for coordinated international action.
Subject of Research: Antibiotic resistance genes (ARGs) in soils; antimicrobial resistance (AMR) environmental impacts
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Web References: http://dx.doi.org/10.1093/nsr/nwag387
References: 10.1093/nsr/nwag387
Image Credits: ©Science China Press
Keywords: antimicrobial resistance, ARGs, soil metagenomics, croplands, One Health, National Action Plan, blaNDM, mcr, co-selection, spatiotemporal analysis
