Expression of Legionella pneumophila virulence traits in response to growth conditions
Expression of Legionella pneumophila virulence traits in response to growth conditions
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DOI：
10.1128/iai.66.7.3029-3034.1998
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发表时间：
1998-07-01
影响因子：
3.1
通讯作者：
Swanson, MS
中科院分区：
文献类型：
--
作者：
Byrne, B;Swanson, MS
在自然界中，嗜肺军团菌仅作为阿米巴的细胞内寄生虫复制，但它也作为自由生活的微生物在环境中存在。这种机会致病菌如何识别和响应不同的细胞外和细胞内环境的研究确定了以前相关的性状的生长阶段和表达之间的联系，vith毒力。在肉汤培养基中培养时，只有对数期后的嗜肺军团菌具有钠敏感性、细胞毒性、耐盐性、能逃避巨噬细胞溶酶体、感染性和运动性。伴随着巨噬细胞溶解，嗜肺军团菌变得钠敏感和鞭毛化，毒性表型的表达是一种反应：饥饿，因为指数相L，嗜肺菌成为细胞毒性，钠敏感，并在肉汤孵育后，从静止相培养物运动，除了补充了氨基酸的时候。总之，这些数据表明，虽然营养丰富，细胞内L，嗜肺军团菌生物体致力于复制;当氨基酸成为限制，后代表达毒力因子，以逃避用过的主机，分散和生存在水生环境中，并重新建立一个受保护的细胞内生态位有利于生长。
In nature, Legionella pneumophila replicates exclusively as an intracellular parasite of amoebae, but it also persists in the environment as a free-living microbe. Studies of how this opportunistic pathogen recognizes and responds to distinct extracellular and intracellular environments identified a link between the growth phase and expression of traits previously correlated,vith virulence. When cultured in broth, only post-exponential-phase L, pneumophila was sodium sensitive, cytotoxic, osmotically resistant, competent to evade macrophage lysosomes, infectious, and motile, Likewise, the L, pneumophila phenotype changed during growth in macrophages, During the intracellular replication period, this bacterium was sodium resistant and lacked flagella; concomitant with macrophage lysis, L, pneumophila became sodium sensitive and flagellated, Expression of the virulent phenotype was a response: to starvation, since exponential-phase L, pneumophila became cytotoxic, sodium sensitive, and motile after incubation in broth from stationary-phase cultures, except when it was supplemented with amino acids. Together, these data indicate that while nutrients are plentiful, intracellular L, pneumophila organisms are dedicated to replication; when amino acids become limiting, the progeny express virulence factors to escape the spent host, to disperse and survive in the aquatic environment, and to reestablish a protected intracellular niche favorable for growth.