宏基因组二代测序技术在肺泡灌洗液病原检测中的应用

Application of metagenomic next-generation sequencing in pathogen diagnosis of bronchoalveolar lavage fluids

目的:为了探讨宏基因组二代测序技术(mNGS)对于下呼吸道标本的病原诊断效率。方法:选取65例被诊断为肺部感染的病例,行支气管肺泡灌洗,取2份标本,1份做mNGS,另外一份同时做细菌培养,真菌培养,抗酸染色和六胺银染色。通过分析mNGS和传统培养与涂片染色的检出病原分布,检出阳性率,对比两者的检出效率。通过分析mNGS阳性组和mNGS阴性组的实验室检查,并发症,预后,平均住院时间等临床资料,来分析mNGS检测对于临床诊疗的作用。结果:mNGS的总体检出阳性率为72.30%(47/65),同时进行的培养总体阳性率为38.46%(25/65),两者具有显著差异P<0.05;耶氏肺孢子菌和结核分枝杆菌的mNGS检出率分别为10.77%(7/65)和6.15%(4/65),六胺银染色检出阳性率为1.54%(1/65),抗酸染色检测阳性率为6.15%(4/65),mNGS可提升耶氏肺孢子菌的检出率,而对结核分枝杆菌的检出无明显优势,此外mNGS检测到35例混合感染,而培养方法只检测到7例细菌和真菌的混合感染。对比分析mNGS阳性组和mNGS阴性组的临床资料发现mNGS阳性组和mNGS阴性组的CRP水平、抗生素调整率、平均机械通气时间、平均住院时间分别为:83.55±73.33和33.55±23.51、61.70%和33.33%、5.95±8.04天和13.94±15.26天、18.41±13.29天和30.17±21.49天,它们具有显著性差异(P<0.05)。结论:呼吸道肺泡灌洗液的mNGS对于下呼吸道感染患者的病原检测具有很好的作用,能够显著提高病原检出率,并且能够检测混合感染,提高特殊病原体的检出效率,对于及时调整抗生素的使用和缩短住院时间,改善预后有十分重要的作用,因而对于重症患者应尽早进行mNGS的检测。

Objective:Compare the pathogen diagnosis competence of metagenomicnext-generation sequencing technology(mNGS)and traditional methods in lower respiratory tract specimens.Methods:Bronchoalveolar lavage fluids of 65 lung infection patients was subjected to mNGS,meanwhile bacterial culture,fungal culture,acid-fast staining and hexamine silver staining was conducted with the same specimen.The pathogen spectrum and positive rate of mNGS and traditional methods was compared.Clinical data such as laboratory results,complications,prognosis,average length of hospitalization of the mNGS-positive group and mNGS-negative group was analyzed to evaluate whether mNGS was beneficial to clinical therapy.Results:The overall positive rate of mNGSwas 72.30%(47/65),while that of culture was 38.46%(25/65).The detection rate of pneumocystis jiroveci and mycobacterium tuberculosis by mNGS was 10.77%(7/65)and 6.15%(4/65),the positive rate of hexamine silver staining was 1.54%(1/65),and the positive rate acid-fast staining was 6.15%(4/65),mNGS can increase the detection rate of Pneumocystis jiroveci but difference is not obvious in mycobacterium tuberculosis.In addition,35 cases of mixed infection were detected by mNGS,while only 7 cases of mixed infection were detected by culture.CRP level,antibiotic adjustment rate,average mechanical ventilation time,and average hospitalization time of the mNGS positive group and the mNGS negative group were 83.55±73.33 versus 33.55±23.51,61.70%versus 33.33%,5.95±8.04 days versus 13.94±15.26 days,18.41±13.29 days versus 30.17±21.49 days respectively.Conclusion:Compare with traditional methods,mNGS can significantly increase the detection rate of pathogen in bronchoalveolar lavage fluids samples,helps in mix infection detection.With the help of mNGS in pathogen detection,doctors can adjust antibiotics timely,and improving the prognosis and shortening the length of hospitalization time.