Bates M N, Maas E, Martin T, Harte D, Grubner M, Margolin T
Epidemiology and Environmental Microbiology Groups, ESR, Kenepuru Science Centre, Porirua.
N Z Med J. 2000 Jun 9;113(1111):218-20.
To investigate the prevalence of Legionella spp. in the hot water systems of a representative sample of Wellington domestic residences with electrically heated hot water systems, and to investigate risk factors (eg water temperature, plumbing materials) for such contamination.
100 households with electrically heated hot water systems in the Wellington area were investigated. Samples of hot water from several hot water outlets were collected, and characteristics of the plumbing system were recorded. Water samples and swabs were cultured and further examined by polymerase chain reaction (PCR) and direct fluorescence antibody (DFA) testing to identify Legionella spp. and serogroups.
No Legionella spp. were isolated by culture. PCR tested positive for Legionella in specimens from twelve residences. Six of these were also positive by DFA testing. The only environmental factor found to be associated with the presence of Legionella was recent plumbing work on the hot water system. Five of the twelve PCR-positive residences, and four of the six DFA-confirmed residences had hot water delivery temperatures in excess of 60 degrees C.
The results suggest that either Legionellae colonise domestic hot water reticulation systems and/or that the organisms are killed during passage through the hot water tank. Both possibilities may be correct. Further work to characterise the microbial ecology of Legionella-positive hot water distribution systems would be useful, as would the development of improved methods for culturing the organisms from potable water.
调查惠灵顿地区具有电加热热水系统的代表性家庭住宅热水系统中军团菌属的流行情况，并调查此类污染的风险因素（如水温、管道材料）。
对惠灵顿地区100户拥有电加热热水系统的家庭进行了调查。从几个热水出口采集热水样本，并记录管道系统的特征。对水样和拭子进行培养，并通过聚合酶链反应（PCR）和直接荧光抗体（DFA）检测进一步检查，以鉴定军团菌属和血清群。
培养未分离出军团菌属。PCR检测显示12户住宅的样本中军团菌呈阳性。其中6户通过DFA检测也呈阳性。发现与军团菌存在相关的唯一环境因素是近期对热水系统进行的管道工程。12户PCR阳性住宅中有5户，6户DFA确认住宅中有4户的热水输送温度超过60摄氏度。
结果表明，要么军团菌在家庭热水管网系统中定殖，要么这些微生物在通过热水箱的过程中被杀死。两种可能性都可能是正确的。进一步研究军团菌阳性热水分配系统的微生物生态学特征将是有用的，开发从饮用水中培养这些微生物的改进方法也将是有用的。
