Effect of temperature conditions on the growth of Legionella species in complex biological systems for wastewater treatment

致病性军团菌属，如嗜肺军团菌，可引起军团病，一种严重的肺部感染，死亡率为5- 10%。它通过吸入来自人造水系统（如废水处理厂）的受污染气溶胶传播。2015年至2019年，欧洲的军团病病例增加了65%。由于废水再利用应用的增加和气候变化，预计源自废水处理厂的军团病病例将增加。后者尤其会增加废水温度，也会影响废水的微生物组成。据我们所知，由于缺乏基础研究，目前还没有一种解决方案来防止军团菌在废水温度较高（>23°C）的废水处理厂中繁殖。本提案的目的是确定有利于致病性军团菌生长的温度条件。从处理工业温废水的五个不同废水处理厂的处理后废水或活性污泥中获得的分离株将在20 °C至40 °C之间的五个不同温度下培养。为了测试动态温度条件的影响，将在指数生长期的中间在短时间内将温度升高5 °C。比较扰动前后军团菌的生长参数。根据我们监测军团菌的经验，选择快速升温5 °C。在废水处理厂。将使用培养方法获得环境军团菌分离株。环境分离株和军团菌属的隶属关系。生物阶段的多样性将通过下一代属特异性测序进行分析。将选择用于温度实验的分离株，其覆盖存在于所有五个废水处理厂中的核心军团菌群落，以及仅存在于特定废水处理厂中的独特军团菌类型。军团菌的多样性和温度从废水中分离出的军团菌环境分离株的依赖性生长将促进我们对废水处理厂作为军团菌生长的生态位的作用的理解。.我们的研究结果可用于提高军团菌在污水处理厂的监测和支持从业人员在发展战略，以管理温度的突然变化，在污水处理和回收设施。

Pathogenic Legionella spp., like Legionella pneumophila, can cause Legionnaire’s disease, a severe lung infection with a mortality of 5-10%. It is transmitted by the inhalation of contaminated aerosols from man-made water systems, such as wastewater treatment plants. Cases of Legionnaires’ disease increased in Europe by 65 % from 2015 to 2019. Legionnaires’ disease cases originating from wastewater treatment plants are expected to increase due to increased wastewater reuse applications and Climate Change. The latter in particular will increase wastewater temperatures, affecting also the microbial composition of wastewaters. To the best of our knowledge, a solution to prevent the multiplication of Legionella in wastewater treatment plants with warm wastewater temperatures (>23°C) is not available due to the lack of fundamental research. The objective of this proposal is to define the temperature conditions favouring the growth of pathogenic Legionella spp. from wastewater treatment plants, considering constant and dynamic temperature conditions.Isolates obtained from treated wastewater or activated sludge of five different wastewater treatment plants, treating industrial warm wastewaters, will be cultivated at five different temperatures between 20 °C and 40 °C. To test the effect of dynamic temperature conditions the temperature will be increased by 5 °C in a short time in the middle of the exponential growth phase. The Legionella’s growth parameters will be compared before and after the perturbation. A fast temperature increase of 5 °C was chosen according to our experience in monitoring Legionella spp. in wastewater treatment plants. The environmental Legionella isolates will be obtained, using the cultivation method. The affiliation of the environmental isolates and the Legionella spp. diversity in the biological stage will be analysed by genus-specific next-generation sequencing. Isolates for the temperature experiment will be selected covering the core Legionella community, present in all five wastewater treatment plants, and the unique phylotypes, only present in specific wastewater treatments plants.The integration of the results coming from the wastewater/wastewater treatment plant characterisation, the Legionella diversity and the temperature-dependent growth of Legionella environmental isolates from wastewater will advance our understanding of the role of wastewater treatment plants as an ecological niche for the growth of Legionella spp. . Our findings may be used to improve Legionella monitoring in wastewater treatment plants and to support the practitioners in the development of strategies to manage with sudden changes in temperature in wastewater treatment and reclamation facilities.