摘要
      抗生素抗性基因（ARGs）的传播影响着水产养殖动物的安全。溶解氧（DO）可以影响ARGs的传播，但其在这一过程中的作用机制尚不清楚。我们对低DO组和对照组进行了实验室育种实验。结合定量PCR和16S rRNA测序研究DO对ARGs传播的影响。缺氧处理显著增加了水产养殖水中铵和亚硝酸盐的积累，并增加了ARGs和可移动遗传元素（MGE）的相对丰度，尤其是对磺酰胺、（flor）/（chloro）/（am）氯霉素、MLSB（大环内酯、林可酰胺和链脲菌素B）和MGE intI-1（临床）类药物具有耐药性的ARGs，与对照DO处理相比，在28天内增加了2.39–95.69%。尽管ARG携带的丰度，特别是红环藻科、Caldilineaceae、环杆菌科、Saprospiraceae、肠杆菌科、鞘氨醇菌科，在低DO组中表现出更高的丰度，这与ARG的垂直传播有关。缺氧处理更有可能促进水平基因转移（HGT）相关途径，包括ABC转运蛋白、双组分系统和群体感应，从而诱导ARGs的HGT。细菌增殖的改变也改变了MGEs的丰度，尤其是intI-1（临床），这也诱导了ARGs的HGT。此外，pearson相关性结果显示，细菌群落功能的演替在ARG增殖中起着最强的作用，其次是细菌群落结构和MGE。我们的研究结果强调了适当的DO浓度在控制ARGs传播，特别是ARGs的HGT方面的重要性。在全球关注食品安全的背景下，我们的研究结果为确保水产品安全和水产养殖的可持续发展提供了重要信息。
Abstract
The transmission of antibiotic resistance genes (ARGs) affects the safety of aquaculture animals. Dissolved oxygen (DO) can affect the transmission of ARGs, but its mechanism of action in this process is unclear. We conducted laboratory breeding experiment with low and control DO groups. Combined quantitative PCR and 16S rRNA sequencing to study the effect of DO on the spread of ARGs. Hypoxia treatment significantly increased the accumulation of ammonium and nitrite in aquaculture water, and it increased the relative abundances of ARGs and mobile genetic elements (MGEs), especially the ARGs resistant to drugs in the categories of sulfonamide, (flor)/(chlor)/(am)phenicol, and MLSB (macrolide, lincosamide and streptogramin B) and the MGE intI-1(clinic), by 2.39–95.69 % in 28 days relative to the control DO treatment. Though the abundance of ARG carries, especially the Rhodocyclaceae, Caldilineaceae, Cyclobacteriaceae, Saprospiraceae, Enterobacteriaceae, Sphingomonadaceae families, showed higher abundance in low DO groups, relating to the vertical transmission of ARGs. Hypoxia treatment is more likely to promote the horizontal gene transfer (HGT)-related pathways, including ABC transporters, two component system, and quorum sensing, thus to induce the HGT of ARGs. The changed bacterial proliferation also altered the abundance of MGEs, especially intI-1(clinic), which induced HGT of ARGs as well. Additionally, pearson correlation results revealed that the succession of bacterial community function played the strongest role in ARG proliferation, followed by bacterial community structure and MGEs. Our results highlight the importance of suitable DO concentration in controlling the spread of ARGs especially the HGT of ARGs. In the context of global attention to food safety, our results provide important information for ensuring the safety of aquatic products and the sustainable development of aquaculture.

https://www.sciencedirect.com/science/article/abs/pii/S0048969722074058