宏基因组二代测序技术在呼吸系统感染病原学诊断中的应用价值

Evaluation of metagenomic next⁃generation sequencing in the etiological diagnosis of respiratory infection

目的探讨宏基因组二代测序技术(m NGS)在呼吸系统感染病原学诊断中的应用价值。方法选取2020年12月-2021年1月在南方医科大学珠江医院就诊的48例呼吸系统感染者为研究对象,比较痰mNGS检测和痰培养检出病原体的分布、阳性率、符合率、混合感染率,对检出的部分特殊病原体采用PCR、质谱技术进行验证,分析痰mNGS检测的优势和可行性。结果痰mNGS检出75株病原体,其中细菌20株,真菌24株,病毒16株,特殊病原体15株;痰培养检出20株病原体,其中细菌8株,真菌11株,特殊病原体1株。痰mNGS与痰培养检测病原体总符合率为35.42%(17例),阳性符合率为22.92%(11例)。痰mNGS检测病原体阳性率87.50%(42例)和混合感染率60.42%(29例)均显著高于痰培养的阳性率29.17%(14例)和混合感染率8.33%(4例),差异均有统计学意义(χ^(2)=32.685、28.860,P均<0.05)。特殊病原体鹦鹉热衣原体、结核分枝杆菌复合群(MTB)和诺卡菌,验证结果与痰mNGS检测符合率均为100.00%(各2例)。鹦鹉热衣原体患者根据痰mNGS结果确诊,使用敏感性药物后好转率100.00%(2例)。结论痰mNGS检测病原体的阳性率高,在真菌、病毒、特殊病原体及混合感染检测优势明显,能为呼吸系统感染的诊治提供依据。

Objective To determine the value of applying metagenomic next⁃generation sequencing(mNGS)for identifying pathogens in respiratory tract infections.Methods Forty⁃eight patients with a respiratory system infection,treated between December 2020 and January 2021 in Zhujiang Hospital of Southern Medical University,were enrolled in the study,and sputum mNGS detection and sputum culture were performed.The pathogen distribution,positivity rate,consistency rate,mixed infection rate and were compared using the two detection methods.The advantages and feasibility of using mNGS for sputum detection were analyzed.Specific methods were used to validate some specific pathogens.Results Sputum mNGS detected 75 pathogen strains,comprising 20 bacterial strains,24 fungal strains,16 viral strains,and 15 special pathogen strains.Sputum cultures detected 20 pathogen strains,comprising 8 bacterial strains,11 fungal strains,and 1 special pathogen strain.mNGS detection and sputum culture had an overall consistency rate of 35.42%(17 cases)for the detection of pathogens,the positive consistency rate being 22.92%(11 cases).The positive rate of pathogens detected by sputum mNGS was 87.50%(42 cases)and the mixed infection rate was 60.42%(29 cases),which were significantly higher than the positive rate of 29.17%(14 cases)and mixed infection rate 8.33%(4 cases)of sputum culture(χ^(2)=32.685,28.860;all P<0.05).For the special pathogens Chlamydia psittaci,Mycobacterium tuberculosis complex(MTB)and Nocardia,the coincidence rate between the verification results and the sputum mNGS results was 100.00%(2 cases in each).Patients with Chlamydia psittaci were diagnosed according to the results of sputum mNGS,and the improvement rate was 100.00%(2 cases)after using sensitive drugs.Conclusions Sputum mNGS had a high positivity rate for detecting pathogens and had obvious advantages for detecting fungal,viral,special pathogen,and mixed infections.Sputum mNGS detection could provide a basis for the diagnosis and treatment of respiratory system infections.