肺泡灌洗液宏基因组测序在儿童重症肺炎支原体肺炎混合感染中的诊断价值

Diagnostic value of metagenomics next-generation sequencing of bronchalveolar lavage fluid for mixed infection in children with severe Mycoplasma pneumoniae pneumonia

目的探讨肺泡灌洗液(BALF)宏基因组二代测序技术对儿童重症肺炎支原体肺炎(MPP)混合感染的诊断价值。方法选取2019年6月至2019年12月期间因重症MPP需要肺泡灌洗治疗的患儿,所得BALF同时进行传统病原检测和宏基因组的二代测序(metagenomics next-generation sequencing,mNGS)病原检测,分析两种检测方法对重症MPP混合感染的诊断效能。结果共纳入47例重症肺炎支原体肺炎患儿,男23例、女24例,中位年龄58.0(38.0~81.0)月。影像学有肺实变/不张表现的患儿31例,胸腔积液10例,伴有纵隔积气2例。气管镜下有明显黏膜坏死、通气不良或者痰栓形成的患儿28例。47例患儿的BALF同时进行传统病原检测和mNGS检测,两种检测方法检出肺炎支原体均为阳性。BALF传统病原检测中,2例(4.3%)检测出混合感染;mNGS检测中,23例(48.9%)检测出混合感染,显著高于传统病原检测,差异有统计学意义(P<0.001)。mNGS检出混合感染占前3位的病原分别为腺病毒7型(11例,23.4%)、肺炎链球菌(5例)和脓肿分枝杆菌(5例)。结论在儿童重症MPP中,BALF mNGS对混合感染的检出率比传统检测方法更高,尤其对合并病毒感染的检测,能早期进行病毒分型和病毒载量分析。

Objective To explore the diagnostic value of metagenomics next-generation sequencing(mNGS)of bronchalveolar lavage fluid(BALF)for mixed infection in children with severe Mycoplasma pneumoniae pneumonia(MPP).Methods From June 2019 to December 2019,children with severe MPP who need bronchoalveolar lavage treatment were enrolled.BALF was detected by traditional pathogen detection and mNGS at the same time.BALFs were sent for traditional pathogen detection and metagenomics next-generation sequencing.The diagnostic efficacy of the two detection methods for the mixed infection in severe MPP was analyzed.Results A total of 47(23 males and 24 females)children with severe MPP were enrolled and median age was 58.0(38.0~81.0)months.Radiography showed pulmonary consolidation/atelectasis in 31 cases,pleural effusion in 10 cases,and pneumomediastinum in 2 cases.Bronchoscopy revealed that 28 children had obvious mucosal necrosis,poor ventilation,or phlegm formation.The BALF of 47 children was detected by both traditional pathogen detection and mNGS detection,and both methods detected that all children were Mycoplasma pneumoniae positive.Traditional pathogen detection of BALF found mixed infection in 2 cases(4.3%).By mNGS detection,mixed infection was found in 23 cases(48.9%),which was significantly higher than that in traditional pathogen detection.The difference was statistically significant(P<0.001).The top three pathogens detected by mNGS were adenovirus type 7(11 cases,23.4%),Streptococcus pneumoniae(5 cases)and Mycobacterium abscess(5 cases).Conclusions The BALF mNGS has a higher detection rate of mixed infection in pediatric severe MPP than traditional detection methods,especially for the detection of combined virus infection.It is helpful for early virus typing and viral load analysis.