摘要
      水中的悬浮颗粒可以遮蔽微生物和污染物。然而，水生环境中自由生活（FL）或颗粒附着（PA）细菌中新出现的污染物抗生素抗性基因（ARGs）的研究较少。在这项研究中，我们使用高通量定量PCR技术和16S rRNA基因测序，比较了黄河四个季节的自由生活和颗粒附着ARGs。我们的研究结果表明，自由生活的水和颗粒物都以四环素和β-内酰胺酶抗性基因为主。在黄河中，无论季节如何，PA ARGs的绝对丰度都高于FL ARGs。PA ARGs和FL ARGs在冬季具有最高的绝对丰度和多样性。移动遗传元件（MGE）是两种尺寸分级ARG的主要驱动因素。然而，与FL-ARG图谱相比，微生物组对PA-ARG谱的影响较小，而重金属对ARGs的影响可以忽略不计。FL-ARG和PA-ARG的群落聚集可以用中性过程来解释。与自由生活方式相比，与人类健康相关的几种机会性病原体（如大肠杆菌）在颗粒物中表现出更高的相对丰度。这些病原体的一部分是潜在的ARG宿主。因此，重要的是从分级细菌中监测ARG和机会病原体，并制定有针对性的策略来管理ARG传播和机会病原体以确保公众健康。
Abstract
Suspended particles in water can shelter both microorganisms and contaminants. However, the emerging pollutants antibiotic resistance genes (ARGs) in free-living (FL) or particle-attached (PA) bacteria in aquatic environments are less explored. In this study, we compared the free-living and particle-attached ARGs during four seasons in the Yellow River using high-throughput quantitative PCR techniques and 16S rRNA gene sequencing. Our results demonstrated that both the free-living water and particles were dominated by tetracycline and beta-lactamase resistance genes. The PA-ARGs had a higher absolute abundance than FL-ARGs in the Yellow River, regardless of the season. Both PA-ARGs and FL-ARGs had the highest absolute abundance and diversity during winter. Mobile genetic elements (MGEs) were the dominant driver for both size-fractionated ARGs. However, the microbiome had less influence on PA-ARG profiles than the FL-ARG profiles, while the effects of the heavy metals on ARGs were negligible. The community assembly of both FL-ARG and PA-ARG can be explained by neutral processes. Several opportunistic pathogens (e.g., Escherichia coli) associated with human health exhibited a higher relative abundance in the particles than during a free-living lifestyle. Parts of these pathogens were potential ARG hosts. As such, it is important to monitor the ARGs and opportunistic pathogens from size-fractionated bacteria and develop targeted strategies to manage ARG dissemination and opportunistic pathogens to ensure public health.

https://www.sciencedirect.com/science/article/abs/pii/S0304389421025322