Abstract：
Although the management of microbes in drinking water is of paramount importance for public health, there remain challenges in comprehensively examining pathogenic bacteria in the water supply system at the species level. In this study, high-throughput sequencing of nearly full-length 16S rRNA genes was performed to investigate the changes of the water bacterial community in three large-scale drinking water treatment plants (DWTPs) and their corresponding distribution systems during winter and summer. Our findings revealed significant differences in the bacterial community structure between winter and summer water samples for each DWTP and its distribution management area (DMA). In the groundwater-fed DWTP, selective enrichment of mycobacterial species was observed in both seasons, and the subsequent DMA also exhibited strong selection for specific mycobacterial species. In one of the surface water-fed DWTPs, certain Legionella species present in the source water in winter were selectively enriched in the bacterial community after pre-oxidation, although they were susceptible to the subsequent purification steps. A variety of putative pathogenic species (n = 83) were identified based on our pathogen identification pipeline, with the dominant species representing opportunistic pathogens commonly found in water supply systems. While pathogen removal primarily occurred during the purification processes of DWTPs, especially for surface water-fed plants, the relative abundance of pathogenic bacteria in the DMA water flora was lower than that in the DWTP effluent flora, indicating a diminished competitiveness of pathogens within the DMA ecosystem.
摘要：
尽管饮用水中微生物的管理对公共卫生至关重要，在物种水平上全面检查供水系统中的致病菌仍然存在挑战。在这项研究中,对近全长16SrRNA基因进行高通量测序，以研究冬季和夏季三个大型饮用水处理厂（DWTPs）及其相应分布系统中水细菌群落的变化。我们的发现表明，每个DWTP及其分布管理区（DMA）的冬季和夏季水样之间的细菌群落结构存在显着差异。在地下水供给的DWTP中，在两个季节都观察到分枝杆菌物种的选择性富集，并且随后的DMA还表现出对特定分枝杆菌物种的强烈选择。在一个地表水喂养的DWTPs中，冬季存在于水源水中的某些军团菌在预氧化后选择性地富集在细菌群落中，尽管它们容易受到后续纯化步骤的影响。根据我们的病原体鉴定流程，鉴定了多种推定的致病物种(n=83)，主要物种代表供水系统中常见的机会病原体。虽然病原体去除主要发生在DWTPs的纯化过程中，特别是对于地表水喂养的植物，DMA水体菌群中病原菌的相对丰度低于DWTP出水菌群,表明DMA生态系统中病原体的竞争力下降。
