PDF(Pubmed)
Abstract：
COVID-19 pandemic-related building restrictions heightened drinking water microbiological safety concerns post-reopening due to the unprecedented nature of commercial building closures. Starting with phased reopening (i.e., June 2020), we sampled drinking water for 6 months from three commercial buildings with reduced water usage and four occupied residential households. Samples were analyzed using flow cytometry and full-length 16S rRNA gene sequencing along with comprehensive water chemistry characterization. Prolonged building closures resulted in 10-fold higher microbial cell counts in the commercial buildings [(2.95 ± 3.67) × 105 cells mL-1] than in residential households [(1.11 ± 0.58) × 104 cells mL-1] with majority intact cells. While flushing reduced cell counts and increased disinfection residuals, microbial communities in commercial buildings remained distinct from those in residential households on the basis of flow cytometric fingerprinting [Bray-Curtis dissimilarity (dBC) = 0.33 ± 0.07] and 16S rRNA gene sequencing (dBC = 0.72 ± 0.20). An increase in water demand post-reopening resulted in gradual convergence in microbial communities in water samples collected from commercial buildings and residential households. Overall, we find that the gradual recovery of water demand played a key role in the recovery of building plumbing-associated microbial communities as compared to short-term flushing after extended periods of reduced water demand.
摘要：
由于商业建筑关闭的前所未有的性质，与COVID-19大流行相关的建筑限制增加了重新开放后对饮用水微生物安全的担忧。从分阶段重新开放开始(即，2020年6月),我们从三栋减少用水量的商业大厦和四户被占用的居民家庭抽取了六个月的饮用水样本。使用流式细胞术和全长16SrRNA基因测序以及全面的水化学表征来分析样品。长时间的建筑物关闭导致商业建筑物中的微生物细胞计数[（2.95±3.67）×105个细胞mL-1]比大多数完整的居民家庭[（1.11±0.58）×104个细胞mL-1]高10倍细胞。虽然冲洗减少了细胞计数并增加了消毒残留物，根据流式细胞仪指纹[Bray-Curtis差异（dBC）=0.33±0.07]和16SrRNA基因测序（dBC=0.72±0.20），商业建筑中的微生物群落与居民家庭中的微生物群落仍然不同。重新开放后需水量的增加导致从商业建筑和住宅家庭收集的水样中的微生物群落逐渐趋同。总的来说,我们发现，与长期减少水需求后的短期冲洗相比，水需求的逐渐恢复在建筑物管道相关微生物群落的恢复中起着关键作用。
