摘要
      医院废水处理系统（HWTS）是临床相关抗生素耐药性基因（ARGs）的重要来源和环境库。然而，人们对HWTS中临床废水的抗生素耐药性是如何变化的还知之甚少。在此，通过宏基因组学对三种HWTS中ARGs的基本定量特征（即多样性和丰度）进行了分析。总共检测到属于20种ARG类型的709种ARG亚型，相对丰度范围为1.12×10−5至7.33×10−1拷贝/细胞。值得注意的是，大多数ARG不能通过HWTS中的氯化处理显著去除。这些ARGs被鉴定为对几乎所有主要类别的抗生素都具有耐药性，并包括最后使用的抗生素ARGs，如blaNDM、mcr和tet（X），它们分别以19、5和7种变体大量出现在HWTS中。此外，基于宏基因组组装基因组（MAG）分析的定性分析显示，已鉴定的ARG的假定宿主广泛分布在至少8个优势细菌门中。在107个回收的携带ARG的MAG中，39个编码多抗生素耐药性，16个属于抗生素耐药性病原体。对具有可移动遗传元件的ARGs共现模式的进一步分析表明它们具有潜在的可移动性。ARGs的这些关键定性特征提供了关于其系统发育和遗传背景的进一步信息。本研究揭示了ARGs与耐药性传播、致病性和临床废水健康风险相关的关键特征。
Abstract
Hospital wastewater treatment system (HWTS) is an important source and environmental reservoir of clinically relevant antibiotic resistance genes (ARGs). However, how antibiotic resistome of clinical wastewater changed in HWTS is poorly understood. Herein, the basic quantitative traits (i.e., diversity and abundance) of ARGs in three HWTSs were profiled by metagenomics. In total, 709 ARG subtypes belonging to 20 ARG types were detected with relative abundance ranging from 1.12 × 10−5 to 7.33 × 10−1 copies/cell. Notably, most ARGs could not be significantly removed by chlorination treatment in the HWTS. These ARGs were identified to confer resistance to almost all major classes of antibiotics and include ARGs of last-resort antibiotics, such as blaNDM, mcr and tet(X) which were abundantly occurred in HWTS with 19, 5 and 7 variants, respectively. Moreover, qualitative analysis based on metagenome-assembled genome (MAG) analysis revealed that the putative hosts of the identified ARGs were broadly distributed into at least 8 dominant bacterial phyla. Of the 107 ARG-carrying MAGs recovered, 39 encoded multi-antibiotic resistance and 16 belonged to antibiotic resistant pathogens. Further analysis of co-occurrence patterns of ARGs with mobile genetic elements suggested their potential mobility. These key qualitative traits of ARGs provided further information about their phylogeny and genetic context. This study sheds light on the key traits of ARGs associated with resistance dissemination and pathogenicity and health risks of clinical wastewater.

https://www.sciencedirect.com/science/article/abs/pii/S0043135423000490