PA1864基因敲除对铜绿假单胞菌毒力及致病性的影响

Effect of PA1864 gene knockout on virulence and pathogenicity of Pseudomonas aeruginosa

目的评价PA1864基因在铜绿假单胞菌(PA)毒力及致病性中的作用。方法比较野生菌株(PAO1与PA1864基因敲除菌株(△PA1864)急性感染小鼠肺或A549肺癌细胞后细菌毒力表型及致病性的差异,包括小鼠的生存率、肺水肿、组织损伤,细胞活力,PAO1和△PA1864菌株分泌性毒力因子、Ⅲ型毒力蛋白分泌系统(T3SS)及群体感应(QS)系统表达情况等。结果 PA1864基因敲除后,菌体对宿主的致病性及细胞毒性降低,细菌泳动能力、T3SS相关蛋白(ExoS、PcrV)表达下调,而绿脓素合成量增加,喹诺酮QS系统信号分子合成增加。结论 PA1864基因可促进PA毒力,且该调节作用可能与喹诺酮QS系统有关。

Objective To evaluate the role of PA1864 gene in the virulence and pathogenicity of Pseudomonas aeruginosa (PA). Methods Difference in virulence phenotype and pathogenicity between wild type (PAO1) and PA1864 gene knockout strain (△PA1864) which acutely infected mice lung or A549 lung cancer cells was compared, including the survival rate of mice, pulmonary edema, tissue damage, cell viability, secretory virulence factors of PAO1 and △PA1864 strains, type Ⅲ secretion system (T3SS) of toxic protein and quorum sensing(QS) system and so on. Results When PA1864 gene was knocked out, pathogenicity and cytotoxicity of bacteria to host decreased, bacterial swimming motility and expression of T3SS-related proteins (ExoS, PcrV) were down-regulated, while synthesis of pyocyanin increased, synthesis of signal molecules in quinolone QS system increased. Conclusion PA1864 gene can promote PA virulence, and this regulation may be related to quinolone QS system.