Department of Microbiology and Immunology, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, USA.
J Water Health. 2010 Mar;8(1):71-82. doi: 10.2166/wh.2009.129.
Legionella and Mycobacterium can proliferate within free-living amoebae (FLA) where they are protected from disinfectants at concentrations that can kill bacteria but not protozoa. Despite effective treatment of drinking water, microbes can enter water utility distribution systems (DS) and hence the plumbing within building premises. Additionally, biofilm formation may account for the persistence of microbes in the DS. In the present study a domestic water tap in north-central United States (USA) was sampled in March and September 2007 and analysed for FLA, Legionella and Mycobacterium. Identification of organisms was determined by growth on specific culture media, light and electron microscopy, and amplification of DNA probes specific for each organism. In both the spring and fall samples, amoebae, Legionella and Mycobacterium were detected. However, Acanthamoeba was prominent in the spring sample whereas Vahlkampfia and Naegleria were the amoebae detected in the autumn. Bacterial proliferation in laboratory cultures was noticeably enhanced in the presence of amoebae and biofilms rapidly formed in mixed amoebae and bacteria cultures. It is hypothesized that temperature affected the dynamics of FLA species population structure within the DS and that pathogenic bacteria that proliferate within FLA, which are themselves opportunistic pathogens, pose dual public health risks.
嗜肺军团菌和分枝杆菌可在自由生活阿米巴（FLA）中增殖，在这些阿米巴中，它们可免受消毒剂的侵害，而这些消毒剂的浓度可杀死细菌但不会杀死原生动物。尽管饮用水的处理效果很好，但微生物仍可能进入水公用事业分配系统（DS），从而进入建筑物内的管道。此外，生物膜的形成可能是 DS 中微生物持续存在的原因。在本研究中，2007 年 3 月和 9 月在美国（USA）中北部的一个家庭水龙头进行了采样，并对 FLA、嗜肺军团菌和分枝杆菌进行了分析。通过在特定培养基上的生长、光镜和电子显微镜观察以及针对每种生物体的 DNA 探针的扩增来确定生物体的鉴定。在春季和秋季的样本中均检测到了阿米巴、嗜肺军团菌和分枝杆菌。然而，在春季样本中，棘阿米巴属更为突出，而在秋季样本中则检测到了沃氏嗜热菌属和内格里亚属。在存在阿米巴和生物膜的情况下，实验室培养物中的细菌增殖明显增强，并且在混合的阿米巴和细菌培养物中迅速形成生物膜。据推测，温度会影响 DS 内 FLA 物种群体结构的动态，而在 FLA 中增殖的致病性细菌本身就是机会性病原体，这会带来双重公共卫生风险。
