Abstract：
In premise plumbing, microbial water quality may deteriorate under certain conditions, such as stagnation. Stagnation results in a loss of disinfectant residual, which may lead to the regrowth of microorganisms, including opportunistic pathogens. In the present study, microbial regrowth was investigated at eight faucets in a building over four seasons in one year. Water samples were obtained before and after 24 h of stagnation. In the first 100 mL after stagnation, total cell counts measured by flow cytometry increased 14- to 220-fold with a simultaneous decrease in free chlorine from 0.17-0.36 mg L-1 to <0.02 mg L-1. After stagnation, total cell counts were not significantly different among seasons; however, the composition of the microbial community varied seasonally. The relative abundance of Pseudomonas spp. was dominant in winter, whereas Sphingomonas spp. were dominant in most faucets after stagnation in other seasons. Opportunistic pathogens, such as Legionella pneumophila, Mycobacterium avium, Pseudomonas aeruginosa, and Acanthamoeba spp., were below the quantification limit for real-time quantitative PCR in all samples. However, sequences related to other opportunistic pathogens, including L. feeleii, L. maceachernii, L. micdadei, M. paragordonae, M. gordonae, and M. haemophilum, were detected. These results indicate that health risks may increase after stagnation due to the regrowth of opportunistic pathogens.
摘要：
在前提管道中，微生物水质在某些条件下可能会恶化，比如停滞。停滞导致消毒剂残留的损失，这可能导致微生物的再生，包括机会性病原体。在本研究中,在一年的四个季节中，对建筑物的八个水龙头进行了微生物再生研究。在停滞24小时之前和之后获得水样。在停滞后的第一个100mL，流式细胞术测量的总细胞计数增加14至220倍，同时游离氯从0.17-0.36mgL-1减少至<0.02mgL-1。停滞之后,不同季节的细胞总数没有显著差异；然而，微生物群落的组成随季节变化。假单胞菌属的相对丰度。在冬天占主导地位，而鞘氨醇单胞菌属。在其他季节停滞后，大多数水龙头都占主导地位。机会性病原体，比如嗜肺军团菌,鸟分枝杆菌,铜绿假单胞菌,和棘阿米巴。,低于所有样品中实时定量PCR的定量限。然而,与其他机会病原体相关的序列，包括L.feeleii,L.maceachernii,L.Micdadei,副甲，M.gordonae,和嗜血杆菌,被检测到。这些结果表明，由于机会性病原体的再生长，停滞后健康风险可能会增加。
