通气机相关真菌性肺炎的流行病学研究

Ventilator Associated Fungal Pneumonia: An Epidemiological Study

目的探讨通气机相关真菌性肺炎(VAFP)的流行病学特点,确定VAFP病原菌的种类和来源。方法入住重症监护病房(ICU)>48 h的危重症患者142例,分为机械通气组(MV组)和未行机械通气组(对照组),连续自下呼吸道及其他相关部位(如胃、咽部、冷凝液等)采样,培养分离真菌菌株,鉴定不同部位的同一菌种,并行质粒谱型检测。结果MV组中发生VAFP 31例,占36.5%,对照组发生真菌性肺炎11例,占19.3%(P<0.05);MV组白色念珠菌大部分来自胃,再逆行到咽,然后定植气管支气管树;非白色念珠菌和曲霉菌,主要来自气溶胶、冷凝液、空气等,直接定植气管支气管树;本研究念珠菌属构成比发生明显变化,热带念珠菌达45.2%,白色念珠菌为33.3%,其他念珠菌占9.5%。结论MV是引发VAFP的最危险因素之一,VAFP的病原菌不同,感染途径也可能不同。致病菌种发生变异,白色念珠菌所占比例下降,热带念珠菌跃居首位。

OBJECTIVE To investigate the epidemidogical characteristics of ventilator associated fungal pneumonia （VAFP）, and to determine the species and source of pathogens. METHODS Totally 142 critical patients in ICU over 48 hours were involved, all cases were divided into two groups, namely mechanical ventilator group （MV group） and non-mechanical ventilator group （control, group）. Samples were continually taken from lower respiratory tract and other related sites （such as stomach, pharynx, condensate, etc）. Fungi were isolated and cultivated, the same fungal species were identified at different sites and then plasmid profiles were analyzed. RESULTS In MV group, 31 cases developed VAFP, the incidence being 36. 5 %. In control group, 11 cases suffered from fungal pneumonia accounted for 19. 3% （P〈 0. 05）. Candida albicans mostly came from stomach and retrograded to pharynx, then resided in trachobrochial tree in MV group. Non-C. albicans and Aspergillus mainly came from aerosol, condensate, air, etc, and directly resided in trachohrochial tree. Candida varied in proportion. C. tropicalis accounted for 45. 2% ,C. albicans for 33. 3%, other candida for 9. 5%. CONCLUSIONS MV is one of the most risk factors to cause VAFP. Different pathogens of VAFP have different infectious routes. Pathogens occur to variation, the proportion of C. albicans decreases, and C. tropicalis ranks first.