PDF(Pubmed)
Abstract：
Increases in phosphate availability in drinking water distribution systems (DWDSs) from the use of phosphate-based corrosion control strategies may result in nutrient and microbial community composition shifts in the DWDS. This study assessed the year-long impacts of full-scale DWDS orthophosphate addition on both the microbial ecology and density of drinking-water-associated pathogens that infect the immunocompromised (DWPIs). Using 16S rRNA gene amplicon sequencing and droplet digital PCR, drinking water microbial community composition and DWPI density were examined. Microbial community composition analysis suggested significant compositional changes after the orthophosphate addition. Significant increases in total bacterial density were observed after orthophosphate addition, likely driven by a 2 log 10 increase in nontuberculous mycobacteria (NTM). Linear effect models confirmed the importance of phosphate addition with phosphorus concentration explaining 17% and 12% of the variance in NTM and L. pneumophila density, respectively. To elucidate the impact of phosphate on NTM aggregation, a comparison of planktonic and aggregate fractions of NTM cultures grown at varying phosphate concentrations was conducted. Aggregation assay results suggested that higher phosphate concentrations cause more disaggregation, and the interaction between phosphate and NTM is species specific. This work reveals new insight into the consequences of orthophosphate application on the DWDS microbiome and highlights the importance of proactively monitoring the DWDS for DWPIs.
摘要：
由于使用基于磷酸盐的腐蚀控制策略，饮用水分配系统（DWDS）中磷酸盐的可用性增加可能会导致DWDS中的营养和微生物群落组成发生变化。这项研究评估了全尺寸DWDS正磷酸盐添加对微生物生态和感染免疫功能低下（DWPI）的饮用水相关病原体密度的影响。使用16SrRNA基因扩增子测序和液滴数字PCR，研究了饮用水微生物群落组成和DWPI密度。微生物群落组成分析表明，添加正磷酸盐后，组成发生了显着变化。添加正磷酸盐后，观察到总细菌密度显着增加，可能是由非结核分枝杆菌（NTM）增加2log10驱动的。线性效应模型证实了磷酸盐添加与磷浓度的重要性，解释了NTM和肺炎支原体密度变化的17％和12％，分别。为了阐明磷酸盐对NTM聚集的影响，比较了在不同磷酸盐浓度下生长的NTM培养物的浮游和聚集体部分。聚集测定结果表明，较高的磷酸盐浓度导致更多的解聚，磷酸盐和NTM之间的相互作用是物种特异性的。这项工作揭示了正磷酸盐应用对DWDS微生物组的影响的新见解，并强调了主动监测DWDS对DWPI的重要性。
