呼吸道吸出物MP-DNA检测对儿童肺炎支原体肺炎诊断的临床意义

Clinical significance of MP-DNA from endotracheal aspirates in diagnosis of Mycoplasma pneumoniae pneumonia in children

摘要:

目的 探讨鼻咽抽吸物(NPA)和肺泡灌洗液(BALF)中肺炎支原体(MP)-DNA 检测对儿童MP 肺炎(MPP)诊断的意义。方法 收集164 例MPP 患儿入院24 h 内的NPA 及BALF,荧光定量PCR 法检测MP-DNA;同时在入院24 h 内及治疗7~10 d 病情好转时采集所有患儿静脉血,ELISA 法检测血清特异性MPIgM。结果 164例患儿NPA的MP-DNA阳性检出率为51.8%,低于双份血清MP-IgM阳性检出率(63.4%)(P=0.044),两者检出一致性中等(Kappa=0.618,P<0.01);BALF 的MP-DNA 阳性检出率为71.3%,与双份血清MP-IgM 阳性检出率比较差异无统计学意义(P>0.05),两者检出一致性好(Kappa=0.793,P<0.01);NPA 的MP-DNA 阳性检出率低于BALF(P<0.01),两者检出一致性中等(Kappa=0.529,P<0.01)。BALF 中MP 的中位拷贝数高于NPA(P<0.01)。NPA 和BALF MP-DNA 的检出率均随病程延长有下降趋势(P<0.05),病程~2 周及~4 周患儿BALF MP-DNA 检出率高于NPA(P<0.05)。结论 BALF 中MP-DNA 检出敏感性高,对临床早期诊断MPP具有重要意义;而NPA MP-DNA 检测可能会引起漏诊。

Abstract:

Objective To compare the detection rates of Mycoplasma pneumoniae (MP) from nasopharyngeal aspirates (NPA) and bronchoalveolar lavage fluid (BALF) in children with pneumonia.Methods A total of 164 hospitalized children with pneumonia were enrolled. NPA and BALF of these children were collected within 24 hours of admission, and MP-DNA was detected by fluorescence quantitative PCR. Venous blood samples of all these children were collected within 24 hours of admission and on days 7-10 of treatment, and serum MP-IgM was detected using ELISA.Results The positive rate of MP-DNA in NAP of the 164 cases was 51.8%, which was lower than 63.4% as the detection rate of MP-IgM in serum (P=0.044), and the two detection rates were moderately consistent with each other (Kappa=0.618, P<0.01). The positive rate of MP in BALF was 71.3%, which was not significantly different with that of MP-IgM in serum (P>0.05), and the detection rates were well consistent (Kappa=0.793, P<0.01). The detection rate of MP in NPA was lower than that in BALF (P<0.01), with moderate consistency between two of them (Kappa=0.529, P<0.01). The median MP copy number in BALF was significantly higher than that in NPA (P<0.01). The MP detection rates in NPA and BALF were significantly different among different courses of disease (P<0.05). As the course of disease extended, the MP detection rates in both NPA and BALF showed a declining trend; children with MP pneumonia of 1-2 weeks' duration and 2-4 weeks' duration had a higher MP-DNA detection rate in BALF than in NPA (P<0.05).Conclusions MP-DNA in BALF has a high sensitivity, with a great significance for early diagnosis of MP pneumonia, while NPA MP-DNA tests may lead to a missed diagnosis.