Fan Qingshan, Bai Jie, Jiao Ting, Zhao Zelong, Hou Fujiang
Pratacultural College, Key Laboratory of Grassland Ecosystem (Ministry of Education), Gansu Agricultural University, Lanzhou 730070, China.
Pratacultural College, Key Laboratory of Grassland Ecosystem (Ministry of Education), Gansu Agricultural University, Lanzhou 730070, China.
J Hazard Mater. 2025 Sep 5;495:139054. doi: 10.1016/j.jhazmat.2025.139054. Epub 2025 Jun 24.
The dissemination of antibiotic resistance genes (ARGs) poses a major global public health challenge, yet transmission mechanisms within extreme ecosystems are poorly understood. Using metagenomics and metagenome-assembled genome (MAG) analysis, we investigated ARG composition, risk, and pathways across a complete Qinghai-Tibet Plateau food chain (soil, earthworm, herbage, yak, pika, snowfinch, herdsman). Contrary to conventional theory, ARG assemblages correlated negatively with microbial diversity. Our MAG-centric approach provided direct evidence that Horizontal Gene Transfer (HGT), including striking bacteria-archaea cross-domain transfer of 18 ARGs, predominates ARG dissemination, with specialized 'ARG reservoir' host phyla (e.g., Pseudomonadota) decoupling ARG functional diversity from overall microbial community structure. Earthworms function as 'ARG bioamplifiers', enriching 79.81 % of soil ARGs and contributing 49.43 % to herbage. Crucially, apex consumers (snowfinches, herdsmen) are not merely recipients; their feces drive a significant 'reverse contribution' of high-risk ARGs back into the ecosystem, establishing a complete circular ARG feedback network. Herdsman feces contained all Rank I-IV high-risk ARGs, while snowfinch feces held Rank II/IV, highlighting human activities' impact on escalating ARG risks in this extreme setting. These findings, particularly the novel HGT mechanisms and host specialization insights, challenge the traditional unidirectional transmission model, presenting a new paradigm for managing antibiotic resistance risks in extreme ecosystems within the One Health framework.
抗生素抗性基因（ARGs）的传播构成了一项重大的全球公共卫生挑战，然而人们对极端生态系统中的传播机制却知之甚少。我们利用宏基因组学和宏基因组组装基因组（MAG）分析，研究了青藏高原完整食物链（土壤、蚯蚓、牧草、牦牛、鼠兔、雪雀、牧民）中的ARG组成、风险和传播途径。与传统理论相反，ARG组合与微生物多样性呈负相关。我们以MAG为中心的方法提供了直接证据，表明水平基因转移（HGT），包括18种ARG在细菌和古菌之间惊人的跨域转移，在ARG传播中占主导地位，具有特殊的“ARG储存库”宿主门类（如假单胞菌门）使ARG功能多样性与整体微生物群落结构脱钩。蚯蚓起到“ARG生物放大器”的作用，富集了79.81%的土壤ARG，并为牧草贡献了49.43%。至关重要的是，顶级消费者（雪雀、牧民）不仅仅是接受者；它们的粪便将高风险ARG大量“反向贡献”回生态系统，建立了一个完整的循环ARG反馈网络。牧民粪便中含有所有I-IV级高风险ARG，而雪雀粪便中含有II/IV级，凸显了人类活动对这一极端环境中ARG风险升级的影响。这些发现，特别是新的HGT机制和宿主特异性见解，挑战了传统的单向传播模型，为在“同一个健康”框架下管理极端生态系统中的抗生素抗性风险提供了新的范例。
