医院获得性肺炎发病时间对病原构成影响的回顾性队列研究

A retrospectie cohort study of the influence of time of hospital-acquired pneumonia onset on pathogen constitution

目的了解不同时间发生的医院获得性肺炎(HAP)病原体构成及抗菌药物敏感性的差异.方法在北京、上海和广州6所大学教学医院回顾调查2001年1月至2003年12月间有呼吸道标本培养致病菌阳性的HAP病例,记录患者一般资料、高危因素、HAP严重程度及致病菌药敏试验结果.所有资料用SPSS 12.0统计软件进行汇总分析,比较早、中、晚发HAP的危险因素、病原体构成及其抗菌药物敏感性的差异.结果共有562例患者入选,入院时间≤5 d发病者(早发)136例,6～14 d发病者(中发)326例,≥15 d发病者(晚发)100例.不同时间发生的HAP的高危因素有所差异:抗生素使用率由早期的68.4%增至晚期的88.0%(P=0.002),入住重症监护室(ICU)由29.4%增加至46.0%(P=0.03),免疫功能受损由1.5%增至15.0%(P=0.001).分离出致病菌918株,其中铜绿假单胞菌(171株)、金黄色葡萄球菌(148株)、不动杆菌(148株)、克雷伯菌(132株)和肠杆菌属细菌(81株)为最多见的前5位致病菌.统计学分析显示不同发病时间的HAP中,病原体构成比较有统计学意义(P<0.05):早发性HAP以克雷伯菌最常见(18.3%),肺炎链球菌(2.4%)和嗜血杆菌(4.3%)占有一定比例;而晚发性HAP以铜绿假单胞菌(24.2%)和耐甲氧西林的金黄色葡萄球菌(MRSA)(19.3%)为主,未发现肺炎链球菌和嗜血杆菌.HAP病原体对头孢曲松的敏感性受发病时间、高危因素及病情严重程度影响明显,在早发、无高危因素的轻中症HAP,肺炎病原菌对头孢曲松的敏感性为80%,而晚期重症HAP病原菌的敏感性不足50%.结论不同发病时间HAP的病原体构成和对抗菌药物的敏感性具有明显差别,早发、轻中症病例对头孢曲松的敏感菌多见,而晚发、重症病例中则耐药菌显著增加.

Objectie To study the influence of duration of hospitalization on etiologic agent and antibiotic-resistance of hospital-acquired pneumonia(HAP). Methods Cases of HAP were patients hospitalized in Fudan Uniersity Zhongshan Hospital,Ruijin Hospital,Beijing Hospital,Zhongshan Uniersity Affiliated Third Hospital,Guangzhou Medical College Affiliated Hospital and Guangdong People′s Hospital. These patients were hospitalized from January 2001 to December 2003,and the diagnosis of HAP was made based on positie respiratory specimen cultures. Clinical data including time of HAP onset,seerity of illness,risk factors,isolated bacteria and antimicrobial susceptibility were collected and analyzed. Statistical analysis was performed with the SPSS 12.0 software. Results A total of 562 cases of HAP were recruited,including 136 cases of early-onset pneumonia(time of onset≤5 d),326 cases of middle-onset pneumonia(time of onset 6-14 d) and 100 cases of late-onset pneumonia(time of onset≥15 d). The rate of prior antibiotic use increased from 68.4% in the early-onset group to 88.0% in the late-onset group(P=0.002);ICU admission increased from 29.4% to 46.0%(P=0.03),and immunosuppression increased from 1.5% to 15%(P=0.001). A total of 918 strains of bacteria were isolated,the most common pathogens being Pseudomonas aeruginosa (18.6%),Staphylococcus aureus(16.1%),Acinetobacter spp(16.1%),Klebsiella spp(14.4%) and Enterobacter spp(8.8%). Early-onset HAP were more commonly caused by Klebstella(18.3%),while the main etiologic agents for late-onset HAP were Pseudomonas aeruginosa(24.2%) and Methicillin-resistant Staphylococcus aureus(19.3%). The rates of pneumonia caused by Haemophilus and Streptococcus were 4.3% and 2.4% respectiely in the early-onset cases,but none was found in late-onset cases. The antibacterial actiity of ceftriaxone was influenced by duration of hospitalization,risk factors and seerity of the disease. In less seere early-onset cases without risk factors,the sensitiity of ceftriaxone was 80%. But in seere late-onset cases,it was only 50%. Conclusions There was significant difference in the pathogen constitution and antibiotic-resistance among early-onset,middle-onset and late-onset cases of HAP. The sensitiity of ceftriaxone was high in less seere early-onset cases without risk factors.