摘要
      淡水生态系统是重要的饮用水来源，为细菌和抗生素抗性基因的增殖和传播提供了自然环境。然而，天然淡水中ARGs的生物地理模式及其与大规模细菌群落的关系在很大程度上研究不足。这一点特别重要，因为关于低人为影响环境中ARGs的数据仍然非常有限。我们分别使用16S rRNA基因高通量测序和高通量定量PCR对中国东南部24个水库的细菌群落的生物地理模式及其ARG图谱进行了表征。我们发现细菌群落的组成和ARG谱都表现出显著的距离衰减模式。然而，与细菌群落相比，ARG剖面在不同水体之间表现出更大的差异，并且细菌群落与ARG剖面之间的关系较弱。细菌群落的生物地理模式同时受到随机和确定性过程的驱动，而ARG剖面则不能用随机过程来解释，这表明在相对较低的人类影响下，内陆水域的细菌群落组成和ARG剖面在大范围内脱钩。总体而言，本研究概述了细菌群落和ARG分布的生物地理模式和驱动机制，可为控制饮用水源中的ARG提供指导和参考。
ABSTRACT
Freshwater ecosystems are important sources of drinking water and provide natural settings for the proliferation and dissemination of bacteria and antibiotic resistance genes (ARGs). However, the biogeographical patterns of ARGs in natural freshwaters and their relationships with the bacterial community at large scales are largely understudied. This is of specific importance because data on ARGs in environments with low anthropogenic impact is still very limited. We characterized the biogeographical patterns of bacterial communities and their ARG profiles in 24 reservoirs across southeast China using 16S rRNA gene high-throughput sequencing and high-throughput-quantitative PCR, respectively. We found that the composition of both bacterial communities and ARG profiles exhibited a significant distance-decay pattern. However, ARG profiles displayed larger differences among different water bodies than bacterial communities, and the relationship between bacterial communities and ARG profiles was weak. The biogeographical patterns of bacterial communities were simultaneously driven by stochastic and deterministic processes, while ARG profiles were not explained by stochastic processes, indicating a decoupling of bacterial community composition and ARG profiles in inland waters under relatively low-human-impact at a large scale. Overall, this study provides an overview of the biogeographical patterns and driving mechanisms of bacterial community and ARG profiles and could offer guidance and reference for the control of ARGs in drinking water sources.

https://journals.asm.org/doi/full/10.1128/spectrum.00406-22