State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, 163 Xianlin Road, Nanjing, 210023, China.
China Three Gorges Construction Engineering Corporation, Beijing, 100048, China.
Sci Rep. 2023 Aug 1;13(1):12419. doi: 10.1038/s41598-023-39225-z.
Water supply suspension-restoration can occur frequently due to the overhauling of civil infrastructure in developing countries and the shutdown of commercial buildings during the pandemic. For comprehensive insights into the effects of water supply suspension-restoration, this study characterized the variations of the pathogen community composition of the tap water and their infection risk under different water supply scenarios. Metagenomic sequencing revealed a significant change of the human pathogen profiles, among which the most dominant pathogen changed from Pseudomonas aeruginosa (4.91%) to Acinetobacter johnsonii (0.59%). Furthermore, absolute quantification of pathogens by propidium-monoazide-qPCR revealed that the abundance of the three typical pathogens (Pseudomonas aeruginosa, Mycobacterium avium and Salmonella sp.) showed an increase of 2.44 log to 3.60 log immediately after water supply suspension-restoration and did not return to the normal level even after 2-h supply restoration, except for Pseudomonas aeruginosa. Quantitative microbial risk assessment suggested the infection risks of the three pathogens arising from direct utilization of tap water under stable water supply, including dermal exposure and oral intake, were all above the threshold of 10, and evidently increased after water supply suspension-restoration. This study warns us against the risk induced by the pathogens in tap water, especially after water supply suspension-restoration.
由于发展中国家的民用基础设施检修以及大流行病期间商业建筑的关闭，供水中断-恢复事件可能会频繁发生。为了全面了解供水中断-恢复对水质的影响，本研究对不同供水中断-恢复情况下自来水中病原体群落组成的变化及其感染风险进行了特征描述。宏基因组测序揭示了人类病原体图谱的显著变化，其中最主要的病原体从铜绿假单胞菌（4.91%）变为鲍曼不动杆菌（0.59%）。此外，通过吖啶橙单增 qPCR 对病原体进行绝对定量发现，三种典型病原体（铜绿假单胞菌、鸟分枝杆菌和沙门氏菌）的丰度在供水中断-恢复后立即增加了 2.44 到 3.60 个对数级，即使在恢复供水 2 小时后，仍未恢复到正常水平，除了铜绿假单胞菌。定量微生物风险评估表明，在稳定供水情况下，直接利用自来水会产生三种病原体的感染风险，包括皮肤接触和经口摄入，其风险均高于 10，并且在供水中断-恢复后明显增加。本研究警告我们要注意自来水中病原体带来的风险，尤其是在供水中断-恢复后。
