摘要

      水环境是细菌耐药基因（ARGs）的重要储库，但对ARGs在水体中的高分辨率时间分布的研究非常有限。采用高通量方法分析了亚热带城市水库1年来ARGs的周动态及其与微生物分类群落和环境变量的关系。共检测到197个精氨酸和10个流动基因元件。结果表明，细菌群落具有季节性，而ARGs组成没有表现出季节性，从而表明微生物分类和功能的时间模式是不同步或不耦合的。更重要的是，细菌丰度和群落多样性与17个环境变量的相关性比ARGs强（OTUs为36个显著相关，ARGs为11个显著相关）。然而，随机过程似乎在ARG谱的结构中起着次要的作用，但在细菌分类群落的结构中起着更重要的作用。此外，我们还发现降水和浑浊度与ARGs的丰富度和多样性显著相关，表明多种环境因素以复杂的方式影响ARGs的组成和动态。MGEs含量丰富，与ARGs呈显著正相关，表明MGEs对ARGs的变化具有一定的影响。这是首次对亚热带水体中ARGs的高分辨率动力学进行综述。我们的研究结果有助于在精细的时间尺度上理解ARGs的微生物过程和机理，并为城市水环境的监测、评价和管理提供经验数据。

      Aquatic environments serve as important reservoirs of antibiotic resistance genes (ARGs), but the information on the high-resolution temporal pattern of ARGs in waterbodies is extremely limited. In this study, the weekly dynamics of ARGs and their relationships with microbial taxonomic communities and environmental variables were analyzed in a subtropical urban reservoir over the period of 1 year using high-throughput approaches. In total, 197 ARGs and 10 mobile genetic elements (MGEs) were detected. The results showed that the bacterial community had a seasonal pattern, while ARGs composition did not exhibit seasonality, thereby indicating the asynchrony or decoupling of temporal patterns of microbial taxonomy and function. More importantly, bacterial abundance and community diversity were more strongly correlated with 17 measured environmental variables than ARGs (36 significant correlations for OTUs, 11 for ARGs). However, stochastic processes appeared to have a minor role in the structuring of the ARG profiles, but a more important role in the structuring of bacterial taxonomic communities. Furthermore, we found that precipitation and turbidity were significantly correlated with the richness and diversity of ARGs, suggesting that multiple environmental factors influence the composition and dynamics of ARGs in complex ways. MGEs were abundant and showed significant positive correlations with ARGs, indicating a plausible influence of MGEs on the variation of ARGs. This is the first study which provides an overview of high-resolution dynamics of ARGs in a subtropical waterbody. Our results improve the understanding of microbial processes and mechanisms of ARGs at fine temporal scale, and offer empirical data of use in the monitoring, assessment and management of the urban water environments.

       https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6614491/