Abstract：
Antibiotic resistance gene (ARG) transmission poses significant threats to human health. The effluent of wastewater treatment plants is demonstrated as a hotspot source of ARGs released into the environment. In this study, a synthetic microbiome containing nuclease-producing Deinococcus radiodurans was constructed to remove extracellular ARGs. Results of quantitative polymerase chain reaction (qPCR) showed significant reduction in plasmid RP4-associated ARGs (by more than 3 orders of magnitude) and reduction of indigenous ARG sul1 and mobile genetic element (MGE) intl1 (by more than 1 order of magnitude) in the synthetic microbiome compared to the control without D. radiodurans. Metagenomic analysis revealed a decrease in ARG and MGE diversity in extracellular DNA (eDNA) of the treated group. Notably, whereas eight antibiotic-resistant plasmids with mobility risk were detected in the control, only one was detected in the synthetic microbiome. The abundance of the nuclease encoding gene exeM, quantified by qPCR, indicated its enrichment in the synthetic microbiome, which ensures stable eDNA degradation even when D. radiodurans decreased. Moreover, intracellular ARGs and MGEs and pathogenic ARG hosts in the river receiving treated effluent were lower than those in the river receiving untreated effluent. Overall, this study presents a new approach for removing extracellular ARGs and further reducing the risk of ARG transmission in receiving rivers.
摘要：
抗生素抗性基因(ARG)的传播对人类健康构成重大威胁。废水处理厂的废水被证明是释放到环境中的ARG的热点来源。在这项研究中,构建了含有产生核酸酶的耐辐射异常球菌的合成微生物组，以去除细胞外ARG。定量聚合酶链反应（qPCR）的结果表明，与无D.radiodurans的对照相比，质粒RP4相关的ARG显着减少（超过3个数量级），而土著ARGsul1和移动遗传元件（MGE）intl1减少（超过1个数量级）。宏基因组分析显示，处理组的细胞外DNA（eDNA）中的ARG和MGE多样性降低。值得注意的是,而在对照组中检测到8个具有移动风险的抗生素抗性质粒，在合成微生物组中只检测到一个.核酸酶编码基因exeM的丰度，通过qPCR定量，表明它在合成微生物组中的富集，这确保了稳定的eDNA降解，即使当D.radiodurans减少。此外，接受处理后废水的河流中的细胞内ARG和MGE以及致病性ARG宿主低于接受未处理废水的河流。总的来说,这项研究提出了一种去除细胞外ARG并进一步降低接收河流中ARG传播风险的新方法。
