摘要
      下水道系统是携带抗生素抗性基因（ARGs）的病原体和细菌的蓄水池。然而，最近的高通量研究依赖于基于DNA的技术，这些技术既不能提供细胞的生理状态信息，也不能提供ARGs的表达信息。在这项研究中，从组合和分离的生活污水系统中收集废水和下水道沉积物样本。使用16S rRNA扩增子测序评估代谢活性原核生物群落，并使用mRNA RT-qPCR测量活性转录的ARG丰度。八个测试的ARG中有三个（sul1、blaTEM、tet（G））在选择的样本中是可量化的。与废水相比，下水道沉积物样品具有更丰富的主动转录ARGs。微生物组分析显示，两种基质中都存在代谢活性家族分类群，这些分类群含有临床相关病原体（假单胞菌科、肠杆菌科、链球菌科、Arcobacteriaceae和梭菌科）和引起腐蚀的原核生物（脱硫杆菌科和脱硫弧菌科）。螺旋体科和产甲烷菌在沉积物基质中更常见，而分枝杆菌科在废水中更常见。从16S rRNA测序获得的微生物组具有与16S rNA基因微生物组显著不同的结构。总的来说，这项研究证明了ARGs在下水道系统中的活性转录，并深入了解了不同下水道基质和下水道类型中感兴趣的分类群的丰度和生理状态，这些分类群与基于废水的流行病学、腐蚀和理解下水道溢流期间不同基质造成的危害有关。
Abstract
Sewer systems are reservoirs of pathogens and bacteria carrying antibiotic resistance genes (ARGs). However, most recent high-throughput studies rely on DNA-based techniques that cannot provide information on the physiological state of the cells nor expression of ARGs. In this study, wastewater and sewer sediment samples were collected from combined and separate sanitary sewer systems. The metabolically active prokaryote community was evaluated using 16S rRNA amplicon sequencing and actively transcribed ARG abundance was measured using mRNA RT-qPCR. Three (sul1, blaTEM, tet(G)) of the eight tested ARGs were quantifiable in select samples. Sewer sediment samples had greater abundance of actively transcribed ARGs compared to wastewater. Microbiome analysis showed the presence of metabolically active family taxa that contain clinically relevant pathogens (Pseudomonadaceae, Enterobacteraceae, Streptococcaceae, Arcobacteraceae, and Clostridiaceae) and corrosion-causing prokaryotes (Desulfobulbaceae and Desulfovibrionaceae) in both matrices. Spirochaetaceae and methanogens were more common in the sediment matrix while Mycobacteraceae were more common in wastewater. The microbiome obtained from 16S rRNA sequencing had a significantly different structure from the 16S rRNA gene microbiome. Overall, this study demonstrates active transcription of ARGs in sewer systems and provides insight into the abundance and physiological state of taxa of interest in the different sewer matrices and sewer types relevant for wastewater-based epidemiology, corrosion, and understanding the hazard posed by different matrices during sewer overflows.

https://link.springer.com/article/10.1007/s00248-021-01775-y