Study of the interrelationship between Legionella pneumophila and free-living amoeba under the condition of natural water temperature to solving legionaires' disease

结果表明，L.通过结合培养方法、真实的时间PCR（RTPCR）和EMA处理的真实的时间PCR（EMA RTPCR），并通过透射电子显微镜观察，在15 ℃的温度下，嗜肺阿米巴在卡氏阿米巴细胞内转变为VNC（Viable but not Culturable）模式。另一方面，在多食阿米巴和蠕虫状Haltomannella中未观察到向VNC状态的转变。可培养湖在针对东京地区两条主要河流的固定采样点定期调查河水中未检测到嗜肺细胞。RT-PCR和EMA RT-PCR结合检测到少量活军团菌，但活军团菌数量基本相同，与季节无关。PCR检测自由生活阿米巴（弗拉）结果表明，各采样点以Haltomanella属为主，A。未检测到Castellanii。弗拉物种的缺失表明与L.嗜肺原虫受水温影响或河流水流影响很少有机会接触宿主阿米巴可能是造成这一结果的原因。

It was demonstrated that L. pneumophila shifted into a VNC(Viable but not Culturable) mode inside the Acanthamoeba castellanii cells at a temperature of 15 degrees C by the combination of cultural method, real time PCR(RTPCR) and EMA treated real time PCR(EMA RTPCR), and by transmission electron microscope observation. On the other hand, the shift into VNC state was not observed in Acanthamoeba polyphaga and Haltomannella vermiformis. Culturable L. pneumophila cells were not detected in periodic survey of river water at fixed-sampling points targeting two major rivers in the Tokyo area. A few viable Legionella cells were detected by the combination of RTPCR and EMA RTPCR, however the numbers of viable cells were approximately-same without relation to season. The detection of free-living amoeba(FLA) by PCR showed that the genus Haltomanella was predominant in the sampling points and A. castellanii was not detected. The absence of FLA species that the interrelationship with L. pneumophila is affected by water temperature or few chances to encounter host amoeba by flow of the river might be cause of this result.