Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, Quebec, Canada.
PeerJ. 2024 Apr 30;12:e17197. doi: 10.7717/peerj.17197. eCollection 2024.
Waterborne transmission of the bacterium has emerged as a major cause of severe nosocomial infections of major public health impact. The major route of transmission involves the uptake of aerosolized bacteria, often from the contaminated hot water systems of large buildings. Public health regulations aimed at controlling the mesophilic pathogen are generally concerned with acute pasteurization and maintaining high temperatures at the heating systems and throughout the plumbing of hot water systems, but is often able to survive these treatments due to both bacterium-intrinsic and environmental factors. Previous work has established an experimental evolution system to model the observations of increased heat resistance in repeatedly but unsuccessfully pasteurized populations. Here, we show rapid fixation of novel alleles in lineages selected for resistance to heat shock and shifts in mutational profile related to increases in the temperature of selection. Gene-level and nucleotide-level parallelisms between independently-evolving lineages show the centrality of the DnaJ/DnaK chaperone system in the heat resistance of . Inference of epistatic interactions through reverse genetics shows an unexpected interaction between DnaJ/DnaK and the polyhydroxybutyrate-accumulation energy storage mechanism used by the species to survive long-term starvation in low-nutrient environments.
水传播已成为具有重大公共卫生影响的严重医院感染的主要原因。主要传播途径包括吸入雾化细菌，通常来自大型建筑物污染的热水系统。旨在控制中温病原体的公共卫生法规通常涉及急性巴氏杀菌，并保持加热系统和热水系统管道中的高温，但由于细菌内在和环境因素，通常能够存活这些处理。以前的工作已经建立了一个实验进化系统来模拟在反复但不成功的巴氏杀菌中观察到的耐热性增加的现象。在这里，我们展示了在选择耐热性的谱系中快速固定新等位基因，以及与选择温度升高相关的突变特征的变化。独立进化谱系之间的基因水平和核苷酸水平的平行性表明 DnaJ/DnaK 伴侣系统在耐热性中的中心地位。通过反向遗传学推断上位性相互作用表明，DnaJ/DnaK 与聚羟基丁酸酯积累储能机制之间存在意想不到的相互作用，该机制用于在低营养环境中长期饥饿时生存。
