摘要
      联合污水溢流（CSOs）已成为环境中抗生素耐药性基因（ARGs）的重要来源，而抗生素耐药性组在CSOs事件中的分布和动力学尚不清楚。本研究基于从读取到宏基因组组装基因组（MAGs）的宏基因组学分析，破译了CSO中抗生素残留组分的图谱，并通过持续监测CSO事件阐明了ARGs的动态变化。结果表明，抗生素失活是主要的耐药机制，磺酰胺类、氨基糖苷类和多药耐药是主要的抗生素耐药类型。据推测，抗生素耐药性通常是由排出的下水道沉积物和管道中的CSO而非生活污水决定的。在重叠群水平上测定了抗生素抗性组的宿主范围和迁移率，宿主主要属于变形杆菌属，以假单胞菌属、大肠杆菌属、肠杆菌属和气单胞菌属为主。转座酶（tnpA）、IS91和整合子是与ARGs一起定位的可移动遗传元件（MGE），并组装了一个携带32个ARGs和140个VFGs的MAG。尽管微生物群落直接对CSO抗生素耐药性的变化贡献最大，但MGE引起的风险应引起更多关注。
Abstract
Combined sewage overflows (CSOs) have become an important source of antibiotic resistance genes (ARGs) in the environment, while the distribution and dynamics of antibiotic resistome in the CSOs events have not been well understood. This study deciphered the profiles of antibiotic resitome in the CSOs based on metagenomics analysis from reads to metagenome assembly genomes (MAGs), and the dynamical changes of ARGs were clarified through continuous monitoring of the CSO event. Results showed that antibiotic inactivation was the dominant resistance mechanism, and sulfonamide, aminoglycoside along with multidrug resistance were the dominant antibiotic resistance types. It was speculated that the antibiotic resistome were generally determined by sewer sediment flushed out along with the CSOs not domestic sewage in the pipes. The host range and mobility of the antibiotic resistome were determined at contigs level, and the hosts mainly belonged to the Proteobacteria with the genus of Pseudomonas, Escherichia, Enterobacter and Aeromonas being dominant. The transposase (tnpA), IS91 and integrons were mobile genetic elements (MGEs) located together with ARGs, and a MAG carrying 32 ARGs and 140 VFGs was assembled. Although microbial community contributed most to the changes of antibiotic resistome in the CSOs directly, the risks caused by the MGEs should be paid more attention.

https://www.sciencedirect.com/science/article/abs/pii/S0304389422000656