College of Environmental Sciences and Engineering, Key Laboratory of Water and Sediment Sciences, Ministry of Education, Peking University, Beijing 100871, China; State Environmental Protection Key Laboratory of All Material Fluxes in River Ecosystems, Beijing 100871, China.
College of Environmental Sciences and Engineering, Key Laboratory of Water and Sediment Sciences, Ministry of Education, Peking University, Beijing 100871, China; State Environmental Protection Key Laboratory of All Material Fluxes in River Ecosystems, Beijing 100871, China.
Water Res. 2022 Oct 15;225:119189. doi: 10.1016/j.watres.2022.119189. Epub 2022 Sep 30.
Microbial co-hosts of nitrate reduction genes (NRGs) and antibiotic resistance genes (ARGs) have been recently reported, but their ecology and biochemical role in urban waterways remain largely unknown. Here, we collected 29 surface water and 29 sediment samples in the Huangshui River on the Qinghai-Tibet Plateau during the wet and dry season, and 11 water samples from wastewater treatment plants and wetlands along the river. Using metagenomic sequencing, we retrieved 278 medium-to-high-quality metagenome-assembled genomes (MAGs) of NRG-ARG co-hosts, mainly belonging to the phyla Proteobacteria, Actinobacteriota, and Bacteroidota. Of microorganisms carrying ARGs, a high proportion (75.3%‒94.9%) also encoded NRGs, supporting nitrate reducing bacteria as dominant hosts of ARGs. Seasonal changes in antibiotic levels corresponded to significant variation in the relative abundance of NRG-ARG co-host in both water and sediments, resulting in a concomitant change in antibiotic resistance pathways. In contrast, the contribution of NRG-ARG co-hosts to nitrate reduction was stable between seasons. We identify specific antibiotics (e.g., sulphonamides) and microbial taxa (e.g., Acinetobacter and Hafnia) that may disproportionately impact these relationships to serve as a basis for laboratory investigations into bioremediation strategies. Our study suggests that highly abundant nitrate reducing microorganisms in contaminated environments may also directly impact human health as carriers of antibiotic resistance.
硝酸盐还原基因（NRGs）和抗生素耐药基因（ARGs）的微生物共宿主最近已有报道，但它们在城市水道中的生态和生化作用在很大程度上仍然未知。在这里，我们在青藏高原的湟水河流域的干湿季节收集了 29 个地表水和 29 个沉积物样本，以及沿河流的 11 个污水处理厂和湿地的 11 个水样。使用宏基因组测序，我们从 278 个中等至高质量的 NRG-ARG 共宿主宏基因组组装基因组（MAG）中检索到，主要属于变形菌门、放线菌门和拟杆菌门。携带 ARGs 的微生物中，有很高比例（75.3%‒94.9%）也编码 NRGs，支持硝酸盐还原菌作为 ARGs 的主要宿主。抗生素水平的季节性变化与水和沉积物中 NRG-ARG 共宿主的相对丰度变化显著相关，导致抗生素耐药途径的相应变化。相比之下，NRG-ARG 共宿主对硝酸盐还原的贡献在季节之间保持稳定。我们确定了特定的抗生素（例如磺胺类药物）和微生物类群（例如不动杆菌属和哈夫尼亚菌属），它们可能不成比例地影响这些关系，为实验室调查生物修复策略提供了依据。我们的研究表明，受污染环境中丰度较高的硝酸盐还原微生物也可能作为抗生素耐药性的携带者，直接影响人类健康。
