Tiwari Ananda, Gomez-Alvarez Vicente, Siponen Sallamaari, Sarekoski Anniina, Hokajärvi Anna-Maria, Kauppinen Ari, Torvinen Eila, Miettinen Ilkka T, Pitkänen Tarja
Expert Microbiology Unit, Finnish Institute for Health and Welfare, Kuopio, Finland.
Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland.
Front Microbiol. 2022 Feb 7;12:803094. doi: 10.3389/fmicb.2021.803094. eCollection 2021.
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.
关于饮用水分配系统（DWDSs）中细菌群落抗生素抗性基因（ARGs）和金属抗性基因（MRGs）共现的信息很少。本研究对芬兰五个维护良好的DWDSs中的ARGs和MRGs进行了表征。所研究的DWDSs有不同的原水水源和处理方法。其中两个水厂采用人工回灌地下水（ARGW），处理过程中不进行消毒。其他三个水厂（两个地表水和一个地下水水源）在处理过程中使用紫外线和氯。采集了10个总体水样（每个DWDSs两个），提取环境DNA，然后使用Illumina HiSeq平台进行高通量鸟枪法宏基因组测序。在所有样本中共鉴定出430个ARGs，从未消毒的DWDSs采集的样本中鉴定出的ARGs多样性最高。此外，未消毒的DWDSs中细菌群落的多样性最高。然而，使用消毒剂的DWDSs样本中，ARG读数与16S rRNA基因读数的比例超过两倍，且大多数MRG（即汞和砷抗性基因）含量较高。在对地表水进行消毒处理的水厂中，赋予与抗生素组相关基因（即多药抗性、杆菌肽、β-内酰胺和氨基糖苷抗性基因）的ARGs的总读数和类型以及汞抗性基因增加。本研究结果有助于全面了解DWDSs中的ARGs和MRGs。饮用水中携带抗生素或金属抗性基因的细菌的出现会导致人们直接接触，因此，需要更系统的调查来解读这些抗性组对人类健康的潜在影响。
