Pseudomonas aeruginosa, commonly found in environments, can cause chronic lung disease in immunocompromised patients. In previous study, an aerobic desaturase (DesB) in P. aeruginosa exerted considerable effects on virulence factor production. The objective of this study was to analyze the role of DesB on the virulence traits of P. aeruginosa in the host. For the in vitro experiments, cells and supernatants from wild-type (WT) P. aeruginosa and its desB mutant were collected. The diluted cells were added to the A549 cell monolayer in order to determine cell viability, invasion ability, and/or immune response. For the in vivo experiments, 6-week-old ICR mice were infected with 6-7 log CFU bacterial cells using endotracheal intubation. The ratio of lung weight to body weight and survival rate of each bacterial strain in the lung were measured. The histopathology of lung tissue was also studied. desB mutants exhibited lower cytotoxicity in A549 cells. In addition, more pro-inflammatory cytokines and chemokines were present in desB mutant-treated. In the lungs of mouse model, WT survived longer than desB mutant, and the WT migrated from the lung to the liver and spleen. The results suggest that P. aeruginosa DesB affects the pathogenicity of the organism in the host.

中文翻译：

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铜绿假单胞菌DesB在病原体-宿主相互作用中的作用。

常见于环境中的铜绿假单胞菌可在免疫功能低下的患者中引起慢性肺部疾病。在以前的研究中，铜绿假单胞菌中的好氧去饱和酶（DesB）对毒力因子的产生产生了相当大的影响。这项研究的目的是分析DesB在寄主中铜绿假单胞菌毒力特性上的作用。为了进行体外实验，收集了野生型（WT）铜绿假单胞菌及其desB突变体的细胞和上清液。将稀释的细胞添加到A549细胞单层中以确定细胞活力，侵袭能力和/或免疫应答。对于体内实验，使用气管插管用6-7 log CFU细菌细胞感染6周大的ICR小鼠。测量肺重量与体重的比率以及肺中每种细菌菌株的存活率。还研究了肺组织的组织病理学。desB突变体在A549细胞中表现出较低的细胞毒性。另外，在desB突变体治疗中存在更多促炎性细胞因子和趋化因子。在小鼠模型的肺中，WT的存活时间比desB突变体更长，并且WT从肺迁移到肝脏和脾脏。结果表明铜绿假单胞菌DesB影响宿主中生物体的致病性。