Lu J, Struewing I, Vereen E, Kirby A E, Levy K, Moe C, Ashbolt N
U.S. EPA National Exposure Research Laboratory, Cincinnati, OH, USA.
CSS-Dynamac, Cincinnati, OH, USA.
J Appl Microbiol. 2016 Feb;120(2):509-21. doi: 10.1111/jam.12996. Epub 2016 Jan 5.
This study investigated waterborne opportunistic pathogens (OPs) including potential hosts, and evaluated the use of Legionella spp. for indicating microbial water quality for OPs within a full-scale operating drinking water distribution system (DWDS).
To investigate the occurrence of specific microbial pathogens within a major city DWDS we examined large volume (90 l drinking water) ultrafiltration (UF) concentrates collected from six sites between February, 2012 and June, 2013. The detection frequency and concentration estimates by qPCR were: Legionella spp. (57%/85 cell equivalent, CE l(-1) ), Mycobacterium spp. (88%/324 CE l(-1) ), Pseudomonas aeruginosa (24%/2 CE l(-1) ), Vermamoeba vermiformis (24%/2 CE l(-1) ) and Acanthamoeba spp. (42%/5 cyst equivalent, CE l(-1) ). There was no detection of the following microorganisms: human faecal indicator Bacteroides (HF183), Salmonella enterica, Campylobacter spp., Escherichia coli O157:H7, Giardia intestinalis, Cryptosporidium spp. or Naegleria fowleri. There were significant correlations between the qPCR signals of Legionella spp. and Mycobacterium spp., and their potential hosts V. vermiformis and Acanthamoeba spp. Sequencing of Legionella spp. demonstrated limited diversity, with most sequences coming from two dominant groups, of which the larger dominant group was an unidentified species. Other known species including Legionella pneumophila were detected, but at low frequency. The densities of Legionella spp. and Mycobacterium spp. were generally higher (17 and 324 folds, respectively) for distal sites relative to the entry point to the DWDS.
Legionella spp. occurred, had significant growth and were strongly associated with free-living amoebae (FLA) and Mycobacterium spp., suggesting that Legionella spp. could provide a useful DWDS monitoring role to indicate potential conditions for non-faecal OPs.
The results provide insight into microbial pathogen detection that may aid in the monitoring of microbial water quality within DWDS prior to customer exposures.
本研究调查了包括潜在宿主在内的水源性机会致病菌（OPs），并评估了在全规模运行的饮用水分配系统（DWDS）中，利用军团菌属来指示OPs的微生物水质情况。
为调查一个大城市DWDS中特定微生物病原体的出现情况，我们检测了2012年2月至2013年6月期间从六个地点采集的大量（90升饮用水）超滤（UF）浓缩物。通过定量聚合酶链反应（qPCR）得出的检测频率和浓度估计值如下：军团菌属（57%/85细胞当量，CE l⁻¹）、分枝杆菌属（88%/324 CE l⁻¹）、铜绿假单胞菌（24%/2 CE l⁻¹）、蠕虫阿米巴（24%/2 CE l⁻¹）和棘阿米巴属（42%/5包囊当量，CE l⁻¹）。未检测到以下微生物：人类粪便指示菌拟杆菌（HF183）、肠炎沙门氏菌、弯曲杆菌属、肠出血性大肠杆菌O157:H7、肠道贾第虫、隐孢子虫属或福氏耐格里阿米巴。军团菌属和分枝杆菌属的qPCR信号与其潜在宿主蠕虫阿米巴和棘阿米巴属之间存在显著相关性。军团菌属的测序显示多样性有限，大多数序列来自两个优势菌群，其中较大的优势菌群是一个未鉴定的物种。检测到了包括嗜肺军团菌在内的其他已知物种，但频率较低。相对于DWDS的入口点，远端站点的军团菌属和分枝杆菌属密度通常更高（分别为17倍和324倍）。
军团菌属存在、有显著生长，且与自由生活阿米巴（FLA）和分枝杆菌属密切相关，这表明军团菌属可为DWDS监测提供有用作用，以指示非粪便OPs的潜在情况。
研究结果为微生物病原体检测提供了见解，可能有助于在客户接触之前监测DWDS中的微生物水质。
