Understanding the ecology and virulence of Legionella spp. populations in freshwater systems in Germany, Palestine and Israel - Phase 2

军团菌属细菌可引起水传播感染，导致严重肺炎。在欧洲，70%的所谓军团病(LD)病例来自嗜肺乳杆菌血清群(Sg)1菌株，20%来自其他嗜肺乳杆菌血清型，10%来自其他军团菌物种。相比之下，在中东，大多数军团菌感染是由嗜肺乳杆菌SG3引起的。该项目的总体目标是促进关于淡水系统中军团菌生态、影响其发生的环境因素、毒力潜力和传染性的现有知识，并了解它们向人类的传播。我们将分析调节军团菌丰度的主要环境因素，如放牧和可同化溶解有机碳，因为这些异养细菌在水生生境中的出现高度依赖于这些因素。我们将使用一种基于环境样本和临床分离株的高分辨率诊断的综合分子方法来现场测定军团菌种群的丰度、活性和毒力潜力。结合环境和分子流行病学数据，我们旨在了解军团菌和LD病例的生态学和种群动态之间的联系。该项目将导致对军团菌分子流行病学的新理解，并为预防LD提供新的监测工具和战略。

Bacteria of the genus Legionella cause waterborne infections resulting in severe pneumonia. In Europe, 70% of the cases of the so-called Legionnaires’ disease (LD) originate from strains of L. pneumophila serogroup (Sg) 1, 20% from other L. pneumophila serotypes and 10% from other Legionella species. In contrast, in the Middle East most legionella infections are due to L. pneumophila Sg3. The overall objective of this project is to advance current knowledge on the ecology of legionella in freshwater systems, the environmental factors affecting their occurrence, virulence potential and infectivity and to understand their transmission to humans. We will analyze the major environmental factors regulating the abundance of legionella, such as grazing and assimable dissolved organic carbon, because the occurrence of these heterotrophic bacteria in aquatic habitats is highly dependent on these factors. We will use an integrated molecular approach based on highresolution diagnostics of environmental samples and clinical isolates to determine the abundance, activity and virulence potential of Legionella populations in-situ. Combining environmental and molecular epidemiological data, we aim at understanding the link between ecology and population dynamics of legionella and cases of LD. The project will result in a novel understanding of the molecular epidemiology of legionella and provide new surveillance tools and strategies to prevent LD.