摘要：目的：探讨铜绿假单胞菌中exoU基因表达与?lasI基因缺失及耐药之间的相关性。方法：选择2020年1月-2020年12月我院收集和分离的640株铜绿假单胞菌（Pseudomonas aeruginosa，PA），采用PCR法检测不同来源菌株exoU毒力基因分布，采用荧光定量 PCR 技术观察菌株中转录调控相关基因exoU表达情况以及lasI基因及下游毒力基因表达情况，采用琼脂稀释法对抗菌药物敏感性进行检测；并采用Pearson相关性分析各基因相对表达量之间的关系。结果：640株PA标本来源分布主要为痰液(51.56%)、血液(22.19%)及脓液(14.69%)。exoS+/exoU-基因组合在各来源标本PA中均检出率最高，其在痰液、血液和脓液中检出率分别为56.97%(188/330)、71.83%(102/142)和67.01%(65/97)；药敏结果显示，640株PA对8种抗菌药物均有不同程度耐药，且痰液来源PA菌株对亚胺培南耐药程度高于血液、脓液以及其他来源菌株(P<0.001)。携带exoU基因PA对亚胺培南，氨基糖苷类，氟喹诺酮类，大环内脂类抗菌药物均具有较高耐药率（P<0.001）；且携带exoS基因PA对氨曲南具有较高耐药性(P<0.05)；?lasI基因缺失PA对各抗菌药物的耐药性明显下降（P<0.001），且携带exoU基因PA菌株转录调控相关基因ptrA、与exsA及效应蛋白基因exoU的相对表达量之间均存在显著负相关（r=-0.645，P<0.001；r=-0.587，P<0.001）；携带exoS基因的PA菌株转录调控相关基因ptrA、与exsA及效应蛋白基因exoS的相对表达量之间也存在显著负相关（r=-0.618，P<0.001；r=-0.532，P<0.001）。lasI基因缺失后，其下游毒力基因 lasA、aprX表达水平均显著下降（P <0.001），且lasA、aprX表达水平与lasI基因相对表达量之间均存在显著正相关（r=0.489，P <0.001；r=0.512，P <0.001）。结论：exoU基因表达与铜绿假单胞菌耐药性之间存在显著相关性，其exoU等毒力基因表达及耐药性可能与负调控基因ptrA相关；lasI基因缺失会对铜绿假单胞菌QS系统毒力基因表达以及细菌耐药性产生明显抑制作用。

Abstract: Objective: To investigate the correlation between exoU gene expression in Pseudomonas aeruginosa and lasI gene deletion and drug resistance. Methods: 640 strains of Pseudomonas aeruginosa (PA) were collected and isolated in our hospital from January 2020 to December 2020, and PCR was used to detect the distribution of exoU virulence genes from different sources of strains, and fluorescence quantitative PCR technology was used to observe the expression of transcriptional regulation related gene exoU and the expression of lasI gene and downstream virulence genes in the strain; The agar dilution method was used to detect the sensitivity of antimicrobial drugs; And Pearson correlation was used to analyze the relationship between the relative expression of each gene. Results: The distribution of 640 PA specimens was mainly sputum (51.56%), blood (22.19%) and pus (14.69%). The exoS+/exoU- gene combination has the highest detection rate in PA samples from all sources, and its detection rates in sputum, blood and pus are 56.97% (188/330), 71.83% (102/142) and 67.01, respectively %(65/97); drug sensitivity results show that 640 strains of PA are resistant to 8 kinds of antibacterial drugs to varying degrees, and the sputum-derived PA strain is more resistant to imipenem than blood, pus and other sources Strain (P<0.001). PA carrying exoU gene has a higher resistance rate to imipenem, aminoglycosides, fluoroquinolones, and macrolide antibacterials (P<0.001); PA carrying exoS gene has a higher resistance to aztreonam Resistance (P<0.05); The resistance of PA with lasI gene deletion to various antibacterial drugs was significantly reduced (P<0.001), and there was a significant negative correlation between the relative expression of the transcriptional regulation-related gene ptrA of the PA strain carrying the exoU gene and exsA and the effector gene exoU (r=-0.645, P<0.001; r=-0.587, P<0.001); There was also a significant negative correlation between the relative expression of the transcriptional regulation-related gene ptrA of the PA strain carrying exoS gene and exsA and the effector gene exoS (r=-0.618, P<0.001; r=-0.532, P<0.001). After lasI gene deletion, the expression levels of downstream virulence genes lasA and aprX decreased significantly (P <0.001), and there was a significant positive correlation between the expression levels of lasA and aprX and the relative expression of lasI gene (r=0.489, P < 0.001; r=0.512, P <0.001). Conclusion: There is a significant correlation between the expression of exoU gene and the drug resistance of Pseudomonas aeruginosa. The expression of virulence genes such as exoU and drug resistance may be related to the negative regulatory gene ptrA; The deletion of the lasI gene will significantly inhibit the expression of virulence genes in the QS system of Pseudomonas aeruginosa and the drug resistance of the bacteria.