上下呼吸道吸出物对儿童下呼吸道感染病原学诊断的意义

A comparative study of upper and lower respiratory aspirates on pathogen detection of lower respiratory tract infection in children

目的比较呼吸道感染儿童鼻咽抽吸物(NPA)和肺泡灌洗液(BALF)的病原学差异。方法收集210例下呼吸道感染患儿NPA及BALF,进行多病原联合检测并进行分析。直接免疫荧光法检测7种常见呼吸道病毒,荧光定量PCR法检测肺炎支原体(MP)、肺炎衣原体(CP)及博卡病毒(HBo V),RT-PCR法检测鼻病毒(HRV)及偏肺病毒(h MPV)等,并作细菌培养。结果 210例患儿NPA和BALF病原总阳性检出率为91.9%(193/210),高于NPA检出率75.2%(158/210)及BALF检出率85.2%(179/210),且BALF检出率高于NPA,差异有统计学意义(P均<0.05)。210例患儿细菌总检出率17.1%,NPA与BALF细菌检出率分别为13.3%和8.6%,差异无统计学意义(P=0.118),但菌种检出一致性较差(Kappa=0.262);病毒总检出率28.1%,NPA病毒检出率(24.3%)高于BALF(15.2%),差异有统计学意义(P=0.012),NPA和BALF的HBo V检出一致性较好(Kappa=0.508);MP总检出率为80.0%,BALF的MP检出率(77.6%)高于NPA(53.3%),差异有统计学意义(P=0.000);BALF的MP中位拷贝数为4.28×106,高于NPA的1.31×105,差异有统计学意义(P=0.000)。病程>2周患儿NPA的MP检出率低于病程≤2周的患儿,差异有统计学意义(P<0.01)。结论 NPA的病毒、MP检测可作为下呼吸道感染的参考依据,其与BALF联合检测可提高呼吸道病原学检测敏感性。BALF检测是重症或疑难下呼吸道感染病例病原学的补充。

Objective To study the pathogenic etiology between nasopharyngeal aspirates（NPA） and bronchoalveolar lavage fluid（BALF） in children with lower respiratory infection. Methods Multiple pathogen in NPA and BALF from 210 cases with lower respiratory tract infection was detected. Seven common respiratory virus（respiratory syncytial virus, adenovirus, influenza virus A, influenza virus B, parainfluenza 1, parainfluenza 2, parainfluenza 3） were detected by direct immunofluorescence assay. MP, CP and HBo V were detected by fluorescence quantitative PCR.HRV and h MPV were detected by RT-PCR. Aspirates were cultured for bacteria. The results of pathogen detection in secretions of upper and lower respiratory tract were analyzed. Results Total positive detection rate of NPA and BALF in 210 cases was 91.9%（193/210）, which is higher than that in NPA 75.2%（158/210） and that in BALF 85.2%（179/210）. Bacteria detection rate in NPA was 13.3%（28/210）, and 8.6%（18/210） in BALF, without significant difference（P=0.118）. Bacteria detection rate in NPA and BALF was of poor consistency（Kappa=0.262）. Virus detection rate in NPA was 24.3%, which is higher than that in BALF15.2%. BALF-MP detection rate was 77.6%（163/210）, significantly higher than that in NPA 53.3%（112/210）. There are 95.5%（107/112） cases with positive results in NPA-MP detectioncan also be detected in the BALF-MP. MP copies in BALF were significantly higher than that in NPA（4.28×10^6 vs. 1.31×10^5）, and its positive rate in NPA was still higher than that in BALF. MP detection rate in NPA in children with clinical course of longer than two weeks was much lower than those with clinical course of two weeks or less. Conclusions The pathogen detection of virus and MP in NPA can be used as a reference for lower respiratory tract infection. The joint detection of NPA and BALF can improve the detection power. The sensitivity of virus detection in NPA is higher than that in BALF. NPA pathogen detection of virus and MP is of great important evidence-based medicine in the diagnosis of lower respiratory infection. MP detection rate and its copies in BALF are significantly higher than that in NPA. BALF detection is the supplement of pathogen diagnosis in severe or refractory lower respiratory infections.