ECOLOGICAL AND MOLECULAR RESEARCH OF VAIABLE BUT NON-CULTURABLE LEGIONELLA

嗜肺军团菌是一种水生细菌，是导致人类军团病的原因。自由生活的阿米巴原虫被军团菌寄生，并提供这种细菌复制所需的细胞内环境。然而，在低营养环境中，嗜肺军团菌能够进入非复制性存活但不可培养（VBNC）状态。军团菌的生态学研究。对更好地了解它们在自然环境中的来源、它们进入人造水系统的机制以及使它们能够在水生生境中生存和生长的事实至关重要。在本研究中，将嗜肺军团菌JLP 1087以10（7）个细胞/ml悬浮于含氯的PBS中。通过CFU测量、CFDA直接计数和EtBr直接计数监测细菌数量的减少。在PBS中孵育23分钟后，细胞不再可在常规平板培养基上培养;然而，CFDA仍可检出。向休眠细菌中添加卡氏阿米巴导致嗜肺军团菌JLP 1087复苏至可培养状态。将VBNC军团菌腹腔内感染豚鼠，这被认为是毒力参数。受感染的豚鼠没有发烧，也没有体重减轻，这表明VBNC失去了毒性。

Legionella pneumophila is an aquatic bacterium and is responsible for Legionnaires' disease in humans. Free-living amoebae are parasitized by legionellae and provide the intracellular environment required for the replication of this bacterium. In low-nutrient environments, however, L.pneumophila is able to enter a non-replicative viable but nonculturable (VBNC) state. Ecological studies on Legionella spp. are essential to better understand their sources in the natural environments, the mechanism of their entry into man-made water systems and the fact ors enabling their survival and growth in aquatic habitats. In this study, L.pneumophila JLP1087 was suspended in PBS containing chlorine at 10(7) cells/ml. The decreasing number of bacteria was monitored by CFU measurements, CFDA direct counts, and EtBr direct counts. After 23 mins of incubation in the PBS, the cells were no longer culturable on routine plating media ; however, they were still detectable by CFDA. The addition of Acanthamoeba culbertosoni to the dormant bacteria resulted in the resuscitation of L.pneumophila JLP1087 to a culturable state. The VBNC Legionella were intraperitoneally infected to guinea pigs, which is considered a parameter for virulence. The infected guinea pig developed no fever and no weight loss, suggesting that the VBNC loses their virulence.