摘要

      关于饮用水分配系统（DWDS）中细菌群落中抗生素抗性基因（ARGs）和金属抗性基因（MRGs）共存的信息很少。这项研究对芬兰五个维护良好的DWDS的ARG和MRG进行了表征。所研究的DWDS具有不同的原水来源和处理方法。其中两家自来水厂采用了人工补给地下水（ARGW），在处理过程中没有使用消毒。其他三家自来水厂（两个地表水源和一个地下水水源）在处理过程中使用了紫外线和氯。收集10个散装水样（每个DWDS两个），提取环境DNA，然后使用Illumina HiSeq平台进行高通量霰弹枪宏基因组测序。在从未消毒的DWDS收集的样本中鉴定出ARGs多样性最高的所有样本中，共鉴定出430个ARGs。此外，未经消毒的DWDS含有最高多样性的细菌群落。然而，使用消毒剂的DWDS样本所含ARG读数与16S rRNA基因读数和大多数MRG（即抗汞和砷基因）的比率是前者的两倍多。在用消毒处理地表水的自来水厂中，与抗生素组（即多药耐药性、杆菌肽、β-内酰胺、氨基糖苷和汞耐药性）相关的ARGs基因的总读数和类型增加。这项研究的发现有助于全面了解DWDS中的ARGs和MRGs。饮用水中携带抗生素或金属耐药性基因的细菌的出现会导致人们直接接触，因此，需要更系统的研究来解读这些耐药性对人类健康的潜在影响。

Information on the co-occurrence of antibiotic resistance genes (ARGs) and metal resistance genes (MRGs) among bacterial communities in drinking water distribution systems (DWDSs) is scarce. This study characterized ARGs and MRGs in five well-maintained DWDSs in Finland. The studied DWDSs had different raw water sources and treatment methods. Two of the waterworks employed artificially recharged groundwater (ARGW) and used no disinfection in the treatment process. The other three waterworks (two surface and one groundwater source) used UV light and chlorine during the treatment process. Ten bulk water samples (two from each DWDS) were collected, and environmental DNA was extracted and then sequenced using the Illumina HiSeq platform for high-throughput shotgun metagenome sequencing. A total of 430 ARGs were characterized among all samples with the highest diversity of ARGs identified from samples collected from non-disinfected DWDSs. Furthermore, non-disinfected DWDSs contained the highest diversity of bacterial communities. However, samples from DWDSs using disinfectants contained over double the ratio of ARG reads to 16S rRNA gene reads and most of the MRG (namely mercury and arsenic resistance genes). The total reads and types of ARGs conferring genes associated with antibiotic groups namely multidrug resistance, and bacitracin, beta-lactam, and aminoglycoside and mercury resistance genes increased in waterworks treating surface water with disinfection. The findings of this study contribute toward a comprehensive understanding of ARGs and MRGs in DWDSs. The occurrence of bacteria carrying antibiotic or metal resistance genes in drinking water causes direct exposure to people, and thus, more systematic investigation is needed to decipher the potential effect of these resistomes on human health. 

https://www.frontiersin.org/articles/10.3389/fmicb.2021.803094/full