呼吸机相关性肺炎感染途径分子流行病学研究

目的 用分子流行病学方法研究呼吸机相关性肺炎(ventilator associated pneumonia,VAP)各种感染途径在其发病机制中的作用.方法 采集ICU置入人工气道行机械通气的患者下呼吸道标本、口咽分泌物、气囊上滞留物、胃液、呼吸机管路标本、空气标本,从护理人员手上采集标本进行细菌培养和表型分析;再通过脉冲场凝胶电泳(pulse field gel electrophoresis,PFGE)方法分析所分离菌株是否具有同源性.结果 48例患者中22例发生VAP,其下呼吸道标本细菌培养17例阳性,以G性菌为主,其中铜绿假单胞菌居首位,且为多重耐药菌;对9例患者来源菌株行PFGE分析,6例气囊上滞留物分离菌株与相应下呼吸道分离菌株为同一PFGE型,5例胃液分离菌株与相应下呼吸道分离菌株为同一PFGE型,3例呼吸机管路样品分离菌株与相应下呼吸道分离菌株为同一PFGE型,2例口咽部分泌物分离菌株与相应下呼吸道分离菌株为同一PFGE型.结论 VAP患者下呼吸道病原体与气囊上滞留物、胃液分离菌有很高的同源性,在感染源的防治上应列为重中之重.

Abstract：

Objective To evaluate the role of infection route in the pathogens of ventilator associated pneumonia (VAP) by molecular epidemiological methods. Methods A study was made in artificial airway patients included trachea intubated or tracheotomied patients in intensive care units (ICU). Pathogen cultivation and antibiotic sensitivity test of the samples collected from lower respiratory tract, gastric cavity, oropharynx. ballonet (artificial airway), air (around patients), hand (nurse),ventilator pipeline and seeper bottles were made. The bacteria isolated from all kinds of specimens and showed same biochemical characteristics were analyzed by phenotypic method and pulse field gel electrophoresis (PFGE) to study their homology. Results Twenty two cases of the total 48 intubated patients supported by mechanical ventilation developed VAP. There were 17 patients whose pathogen cultivations of lower respirotery tract sample were positive. Gram negative bacillis were dominating and pseudomonas aeruginosa standed first on the list. Pathogens of ballonet, gastric cavity tallied with pathogens of lower respiratery tract greatly by PFGE analysis. Conclusions The PFGE homologous analysis of pathogen showed that ballonet, gastric cavity were the most important lower respiratory tract infection route in VAP patients. We should pay more attention to them.

Infection route in ventilator associated pneumonia: the molecular epidemiological study

Objective To evaluate the role of infection route in the pathogens of ventilator associated pneumonia (VAP) by molecular epidemiological methods. Methods A study was made in artificial airway patients included trachea intubated or tracheotomied patients in intensive care units (ICU). Pathogen cultivation and antibiotic sensitivity test of the samples collected from lower respiratory tract, gastric cavity, oropharynx. ballonet (artificial airway), air (around patients), hand (nurse),ventilator pipeline and seeper bottles were made. The bacteria isolated from all kinds of specimens and showed same biochemical characteristics were analyzed by phenotypic method and pulse field gel electrophoresis (PFGE) to study their homology. Results Twenty two cases of the total 48 intubated patients supported by mechanical ventilation developed VAP. There were 17 patients whose pathogen cultivations of lower respirotery tract sample were positive. Gram negative bacillis were dominating and pseudomonas aeruginosa standed first on the list. Pathogens of ballonet, gastric cavity tallied with pathogens of lower respiratery tract greatly by PFGE analysis. Conclusions The PFGE homologous analysis of pathogen showed that ballonet, gastric cavity were the most important lower respiratory tract infection route in VAP patients. We should pay more attention to them.