气管导管生物被膜与复发性铜绿假单胞菌呼吸机相关肺炎的相关性

目的：确定机械通气患者气管内导管（ETT）细菌生物被膜（BF）与长期机械通气反复发作铜绿假单胞菌呼吸机相关肺炎（PA－VAP）病原的相关性。方法：应用染色体DNA SpeI限制酶切脉冲场电脉（PFGE）技术和染色体DNA印迹平均链锁聚类分析及相似系数计算方法，前瞻性研究了15例机械通气且反复发作VAP患者的同期ETT－BF，咽拭子和下呼吸道分泌物分离出的铜绿假单胞菌DNA基因型同源性。结果：在15例长期机械通气反复发作VAP患者中，有7例（15次）同时从ETTBF和下呼吸道分泌物中分离出相同DNA基因型的铜绿假单胞菌。有6例是由同一菌株或亚型所致，9例患者间的细菌DNA基因型各不相同，相似水平很低（＜31．2％）。结论：ETT的细菌寄殖和BF形成与VAP病原菌有密切的相关性，是VAP发病机制中的一个重要因素及持续存在的病原来源；反复发作PA－VAP是以原有致病原的持续寄殖及复发为主，而不是发生外源性再感染。

Correlation of endotracheal tube biofilm and recurrent ventilator-associated pneumonia with Pseudomonas aeruginosa

Objective To determine the correlation of endotracheal tube biofilm (ETT BF) and recurrent ventilator associated pneumonia with Pseudomonas aeruginosa (PA VAP) in long term ventilation patients. Methods Pulsed field gel electrophoresis (PFGE) of Spe I enzyme restricted chromosomal DNA was performed to identify the DNA patterns of Pseudomonas aeruginosa from ETT BF, pharynx and lower respiratory tract secretion in 15 VAP patients The chromosomal DNA fingerprint profile of each strain was compared with those from all other strains to calculate the similarity by using the correlation coefficient The strains were then grouped and groups were depicted as a dendrite using the average clustering algorithm. Results When bacteria has been isolated from ETT BF, the same DNA pattern species are isolated from the lower respiratory tract secretion in 7 of 15 patients Recurrent PA VAP is caused by closely related and indistinguishable isolates in 6 of 15 patients All PEGE patterns from 9 patients are different from one another(correlation coefficient <31 2%). Conclusions The close pathogenic relationship between ETT BF and lower airway secretion suggests that adhesive colonization of ETTs may be an important factor in the pathogenesis of VAP