摘要
出身背景
河流生态系统是环境中最重要的抗生素抗性基因库之一，但对抗生素抗性基因在河流生态系统不同生境中分布的发生和控制因素仍知之甚少。在本研究中，使用宏基因组方法来表征中国东部河流生态系统不同生境（根际土壤、表层土壤、底层土壤和沉积物）中ARG的类型及其丰度。采样点位于中国东部不同的河流沿岸，这些河流在地理上是孤立的。采样点和栖息地的细菌群落、移动遗传元素（MGE）、人类活动模式和强度、气候和其他环境因素的差异预计会影响ARG的发生。
后果
ARGs在多样性（44–206个亚型）和丰度（6.85–105.68×/Gb）方面存在高度变异。在同一生境中，除表层大块土壤外，ARG的发生率存在显著的南北差异。南方四种生境的ARGs存在显著差异。同一栖息地ARGs的南北差异主要归因于ARGs不同的发生频率和栖息地选择的组合。南部和北部四个栖息地ARG分布的差异主要归因于ARG的发生频率不同。细菌群落和移动遗传元素（MGE）可以解释观察到的中国东部河流生态系统抗性的变化。特定ARGs与细菌群落和MGE的共现在北部采样点比在南部采样点更频繁，并且共现模式（即ARGs和细菌群落或ARG和MGE）在不同栖息地之间有所不同。此外，除散装土壤外，所有栖息地的建筑用地都与ARG丰度呈显著正相关。
结论
本研究揭示了中国东部河流生态系统的抗性及其控制因素的高度变异。我们呼吁评估河流生态系统中ARG的重要性，以及未来预防和干预ARG传播的必要性。
Abstract
Background
Riverine ecosystems are one of the most important reservoirs of antibiotic resistance genes (ARGs) in the environment, but the occurrence and controlling factors of ARG distribution in different habitats of riverine ecosystems remain poorly understood. In this study, a metagenomic approach was used to characterize ARG types and their abundance in different habitats (rhizosphere soil, surface bulk soil, bottom bulk soil, and sediment) of riverine ecosystems in eastern China. Sampling sites were located along different rivers of eastern China, which are geographically isolated. Differences in bacterial communities, mobile genetic elements (MGEs), pattern and intensity of human activities, climate, and other environmental factors at the sampling sites and habitats were expected to affect ARG occurrence.

Results
ARGs were observed with high variations in diversity (44–206 subtypes) and abundance (6.85–105.68 ×/Gb). There were significant south-north differences in ARG occurrence in the same habitat, except for surface bulk soil. And the significant difference was found in ARGs among four southern habitats. South–north differences in ARGs of the same habitat were mainly attributed to the combination of different occurrence frequencies and habitat selections of ARGs. Differences in ARG profiles among the four habitats in the south and the north were both mainly attributed to the different occurrence frequencies of ARGs. Bacterial communities and MGEs (Mobile genetic elements) could account for the observed variance in the resistome of riverine ecosystems across eastern China. The co-occurrences of specific ARGs with bacterial communities and MGEs were more frequent at the northern sampling sites than in the south, and co-occurrence patterns (i.e. ARGs and bacterial communities or ARGs and MGEs) varied between the habitats. Moreover, building land in all habitats, except bulk soils, showed significant positive correlations with ARG abundance.

Conclusion
This study reveals a high variance in the resistome of riverine ecosystems in eastern China and its controlling factors. We appeal to the importance of assessment of ARGs in the riverine ecosystem and the need for future prevention and intervention of ARG spread.

https://link.springer.com/article/10.1186/s40793-022-00447-9