1 Department of Respiratory Medicine, Luwan Branch of Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China ; 2 Department of Critical Care Medicine, 3 Department of Respiratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China.
J Thorac Dis. 2014 Jun;6(6):810-7. doi: 10.3978/j.issn.2072-1439.2014.03.37.
This study investigated the correlation between the expression of the Las and Rhl quorum-sensing (QS) systems and the communal behavior (motility, biofilm formation, and pyocyanin production) of Pseudomonas aeruginosa (P. aeruginosa) isolated from patients with hospital-acquired pneumonia.
We analyzed 138 P. aeruginosa isolates from 48 patients (30 men and 18 women; age 68.18±15.08 years). P. aeruginosa clinical isolates were assessed for Las and Rhl gene expression and bacterial motility, biofilm formation, and pyocyanin production.
P. aeruginosa swimming, twitching, and swarming motility positively correlated with the expression of LasI, LasR, and RhlI (P<0.05) but not with that of RhlR (P>0.05). At all analyzed time points, a significant positive correlation was found between biofilm formation and the expression of LasI, LasR (P<0.01), and RhlI (P<0.05 for day 1, P<0.01 for days 7 and 14), whereas RhlR expression positively correlated with biofilm formation only on day 14 (P<0.05). On days 1 and 7, positive correlation was observed between pyocyanin production and the levels of LasI and RhlI (P<0.05). In bacterial clearance cases, the expression of QS-related genes and the group behavior of the pathogen did not correlate (P>0.05). However, in cases of persistent P. aeruginosa infection, the changes in LasI and LasR gene expression were positively correlated with those in bacterial motility (P<0.05), and the changes in LasI, LasR, RhlI, and RhlR expression showed a significant positive association with those in biofilm formation (P<0.01).
In patients with hospital-acquired pneumonia, the expression of the Las and Rhl QS genes was associated with bacterial motility, biofilm formation, and pyocyanin production, suggesting an involvement of the QS genes in the clearance of pathogenic P. aeruginosa in patients.
本研究调查了铜绿假单胞菌（P. aeruginosa）中 Las 和 Rhl 群体感应（QS）系统的表达与医院获得性肺炎患者分离株的集体行为（运动性、生物膜形成和绿脓菌素产生）之间的相关性。
我们分析了来自 48 名患者（30 名男性和 18 名女性；年龄 68.18±15.08 岁）的 138 株 P. aeruginosa 分离株。评估了 P. aeruginosa 临床分离株的 Las 和 Rhl 基因表达以及细菌运动性、生物膜形成和绿脓菌素产生。
P. aeruginosa 泳动、蠕动和群集运动与 LasI、LasR 和 RhlI 的表达呈正相关（P<0.05），但与 RhlR 的表达无关（P>0.05）。在所有分析的时间点上，均发现生物膜形成与 LasI、LasR（P<0.01）和 RhlI（第 1 天 P<0.05，第 7 天和第 14 天 P<0.01）的表达呈显著正相关，而 RhlR 的表达仅在第 14 天与生物膜形成呈正相关（P<0.05）。在第 1 天和第 7 天，绿脓菌素的产生与 LasI 和 RhlI 的水平呈正相关（P<0.05）。在清除细菌的情况下，QS 相关基因的表达和病原体的群体行为没有相关性（P>0.05）。然而，在持续的铜绿假单胞菌感染病例中，LasI 和 LasR 基因表达的变化与细菌运动性呈正相关（P<0.05），并且 LasI、LasR、RhlI 和 RhlR 表达的变化与生物膜形成呈显著正相关（P<0.01）。
在医院获得性肺炎患者中，Las 和 Rhl QS 基因的表达与细菌运动性、生物膜形成和绿脓菌素产生有关，这表明 QS 基因参与了患者致病性铜绿假单胞菌的清除。
