1402例小儿急性下呼吸道感染多病原学临床研究

Clinical and Etiological Analysis of 1402 Children With Acute Lower Respiratory Tract Infections

目的通过对昆明地区小儿急性下呼吸道感染(ALRI)的细菌、病毒和非典型病原体检测,探讨ALRI的临床特点、病原体分布与患儿年龄的关系及其流行病学特征。方法选择2005年10月至2007年10月本院收治的1402例ALRI患儿为研究对象,纳入研究组;选择同期在本院健康体检的健康儿童50例纳入对照组(本研究遵循的程序符合本院人体试验委员会制定的伦理学标准,得到该委员会批准,分组征得受试对象家属的知情同意,并与其签署临床研究知情同意书)。两组患儿性别及年龄等比较,差异无统计学意义(P>0.05)。采集两组受试者鼻咽深部分泌物分别进行病原体培养、鉴定和抗原、抗体检测,抗原、抗体的检测采用直接免疫荧光法和间接免疫荧光法。结果本组1402份标本的呼吸道病原总阳性率为82.2%(1153/1402)。其中,细菌、病毒、非典型病原体和混和感染的阳性率分别为28.7%(402/1402),26.0%(365/1402),18.5%(259/1402)和9.1%(127/1402)。病原菌包括:革兰阴性(G-)菌(大肠埃希菌为41.3%、肺炎克雷伯杆菌为15.4%和流感嗜血杆菌为6.0%)占73.1%(294/402),革兰阳性(G+)菌(肺炎链球菌14.4%)占25.6%(103/402),其他菌各占1.2%(5/402)。病毒包括:呼吸道合胞病毒(RSV)、副流感病毒(PIV)Ⅲ型、A型流感病毒(IVA)、PIVⅡ型、腺病毒(ADV)及PIVⅠ型分别为85.5%(312/365),6.6%(24/365),3.3%(12/365),1.9%(7/365),1.9%(7/365)及0.8%(3/365),未检出B型流感病毒(IVB)。非典型病原体包括:肺炎支原体(MP)、嗜肺军团菌1型(LP1)和肺炎衣原体(CPn)分别占62.9(163/259),34.0(88/259)和3.1(8/259)。婴幼儿ALRI的病原体以细菌和病毒为主,RSV流行季节为秋季。随患儿年龄增长,非典型病原体感染率呈增高趋势。小儿细菌与非典型病原体感染无明显季节性。结论昆明地区小儿ALRI的病原体主要为G-菌和RSV;患儿年龄越小,感染率越高;流行特点存在地区差异。

Objective To investigate the clinical, etiological and epidemiological characteristics of acute lower respiratory tract infection （ALRI） in Kunming region. The etiological agents, including bacteria, virus and atypical pathogens were studied in order to determine different characteristics of age distribution of respiratory infectious agents. Methods From October 2005 to October 2007, a total of 1402 hospitalized children with ALRI were included into this study （study group）. Meanwhile, another 50 healthy children who underwent regular physical examination were recruited into control group. The study protocol was approved by the Ethical Review Board of Investigation in Human Being of Children＇s Hospital of Kunming. Informed consent was obtained from each participate. There had no significant difference between two groups on ages and so on. The nasal secretion samples were collected from study group for the bacterial agents culture and identification; viral antigens were detected by direct and indirect immunofluorescent analysis. Results The etiological agents were detected in 402 of 1402 patients （28.79 %）, of which 9. 1% （127/1402） were mixed infections. The bacterial-, viral-, and non-typical etiological agents were identified in 402 （28, 79%）, 365 （26. 0%） and 259 （18. 5%） of 1402 patients with ALRI, respectively . Total positive rate of respiratory pathogens was 82.2% （1153/1402）. The bacterial agents identified from the 402 positive samples mainly consisted of the Gram-negative （G ） bacteria （73. 1%） [E. coli （41.3%）, Klebsiella pneumoniae （15.4%）, Haernophilus inflenzae （6.0%）], and the G＋ bacteria （mainly Streptococcus pneumoniae） was detected as causative agents responsible for ALRI, for incidences of 14.4%. Of 365 virus positive samples, 312 samples （85. 5%） were tested as positive for the respiratory syncytial virus （RSV） antigen, 12 samples testing positive for influenza A virus（IVA）, 7 samples for parainfluenza virus type （PIV） Ⅱ , 24 samples for PIVⅢ and 7 samples for adenovirus （ADV）. No samples testing positive for influenza B virus （IVB）. Non-typical pathogens identified were Mycoplasma pneumoniae （MP）, Legionella pneumoniae type 1 （LP1）, and Chlamydia pneumoniae（CPn）, accounting for 11. 6%, 6.3%, and 0.6% of the total samples, respectively. Bacteria, virus were two main causative agents responsible for ALRI in younger children, whereas non-typical pathogens were frequently observed in elderly children. Bacteria and atypical pathogens infection incidences showed seasonal differences during a year, but the RSV was the main causative agent during a year, especially in autumn. Conclusions G- bacteria and respiratory syncytial virus are the two main local causative agents which were responsible for ALRI in children; the younger the children are, the higher incidence there is. The etiological agents＇ patterns vary from place to place.