Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, Québec, Canada.
Centre de Recherche en Infectiologie Porcine et Avicole (CRIPA), Université de Montréal, Faculté de Médecine Vétérinaire, Saint-Hyacinthe, Québec, Canada.
Appl Environ Microbiol. 2021 Apr 13;87(9). doi: 10.1128/AEM.02975-20.
() is an inhabitant of natural and human-made water systems, where it replicates within amoebae and ciliates and survives within biofilms. When -contaminated aerosols are breathed in, can enter the lungs and may infect human alveolar macrophages, causing severe pneumonia known as Legionnaires' disease. is often found in hot water distribution systems (HWDS), which are linked to nosocomial outbreaks. Heat treatment is used to disinfect HWDS and reduce the concentration of However, is often able to recolonize these water systems, indicating an efficient heat shock response. Tail-specific proteases (Tsp) are typically periplasmic proteases implicated in degrading aberrant proteins in the periplasm and important for surviving thermal stress. In Philadelphia-1, Tsp is encoded by the gene. In this paper, we show that Tsp is important for surviving thermal stress in water and for optimal infection of amoeba when a shift in temperature occurs during intracellular growth. We also demonstrate that Tsp is expressed in the postexponential phase but repressed in the exponential phase and that the -encoded small regulatory RNA Lpr17 shows the opposite expression, suggesting that it represses translation of In addition, our results show that is regulated by CpxR, a major regulator in , in an Lpr17-independent manner. Deletion of CpxR also reduced the ability of to survive heat shock. In conclusion, our study shows that Tsp is likely an important factor for the survival and growth of in water systems. is a major cause of nosocomial and community-acquired pneumonia. is found in water systems, including hot water distribution systems. Heat treatment is a method of disinfection often used to limit the presence of in such systems; however, the benefit is usually short term, as is able to quickly recolonize these systems. Presumably, responds efficiently to thermal stress, but so far, not much is known about the genes involved. In this paper, we show that the Tsp and the two-component system CpxRA are required for resistance to thermal stress when is free in water and when it is inside host cells. Our study identifies critical systems for the survival of in its natural environment under thermal stress.
() 是天然和人工水系统的居民，在那里它在变形虫和纤毛虫内复制，并在生物膜内存活。当 -污染的气溶胶被吸入时， 可以进入肺部，并可能感染人类肺泡巨噬细胞，导致称为军团病的严重肺炎。 通常在热水分配系统 (HWDS) 中发现，HWDS 与医院感染暴发有关。热处理用于消毒 HWDS 并降低 的浓度。然而， 通常能够重新殖民这些水系统，表明其具有有效的热休克反应。尾巴特异性蛋白酶 (Tsp) 通常是周质内蛋白酶，涉及降解周质内异常蛋白质，对于热应激生存很重要。在 Philadelphia-1 中，Tsp 由 基因编码。在本文中，我们表明 Tsp 对于在水中存活热应激以及在细胞内生长过程中温度发生变化时最佳感染变形虫很重要。我们还证明 Tsp 在指数生长期表达，但在指数生长期受到抑制，而 -编码的小调节 RNA Lpr17 表现出相反的表达，表明它抑制 的翻译。此外，我们的结果表明 不受 CpxR 调节，CpxR 是 中的主要调节剂，以 Lpr17 独立的方式。CpxR 的缺失也降低了 耐受热冲击的能力。总之，我们的研究表明 Tsp 可能是 在水系统中生存和生长的重要因素。 是医院获得性和社区获得性肺炎的主要原因。 在水系统中发现，包括热水分配系统。热处理是一种经常用于限制此类系统中 存在的消毒方法；然而，这种好处通常是短期的，因为 能够迅速重新殖民这些系统。推测 对热应激有效作出响应，但到目前为止，人们对涉及的基因知之甚少。在本文中，我们表明，当 自由存在于水中和在宿主细胞内时，Tsp 和双组分系统 CpxRA 是抵抗热应激所必需的。我们的研究确定了 在热应激下其在自然环境中生存的关键系统。
