| Background:Pulmonary infections are among the most common and important infectious diseases.Due to the complexity of the respiratory microbiota and the limitations in sensitivity of conventional diagnostic methods,it is difficult to detect and identify pathogens for pulmonary infection accurately.In recent years,metagenomic next-generation sequencing(mNGS)is emerging as a promising technique for pathogens detection.And mNGS detects bacteria,fungi,viruses,parasites,and other pathogens with an unbiased approach.However,systematic reports on the use of mNGS in pulmonary infection remain scarce.Objective:To compare the pathogenic detection capabilities between mNGS and traditional testing,and clarify the advantages in pathogen detection of mNGS in pulmonary infection.Methods:From July 2018 to May 2019,the clinical data of 245 suspected pulmonary infection patients were retrospectively analyzed.Alveolar lavage,lung puncture,blood,sputum,and pleural effusion were collected for mNGS and traditional pathogenic testing.Compare the positive rate,the detected pathogen distribution between mNGS and traditional pathogenic testing.Results:1.As expected,mNGS increased the sensitivity rate by approximately 38.6%in comparison with that of traditional pathogenic testing(60.0%vs 21.4%;P<0.01),but the consistency of the two methods is not satisfactory(Kappa=0.222).2.93.9%(124/132)of mNGS positive results were consistent with clinical diagnosis and treatment,and the overall clinical compliance was 56.4%(124/220).3.mNGS showed absolutely advantage in pathogens detection(52.2%vs 22.2%for bacteria,P<0.01;45.7%vs 4.9%for fungi,P<0.05),and its ability to detect rare,atypical pathogens which are unidentifiable by traditional testing was highlighted.4.mNGS increased the positive rate by approximately 38.6%in comparison with that of traditional pathogenic testing(60.0%vs 21.4%;P<0.01),both methods were easier to detect pathogens in patients with severe pneumonia.And regardless of the severity of the disease,the ability of mNGS to detect pathogens was always better than that of traditional pathogenic testing(P<0.01).5.The ability of mNGS to detect pathogens was always better than that of traditional pathogenic testing regardless of receiving mechanical ventilation in severe pneumonia patients(P<0.01).Patients in the mechanical ventilation group were infected more pathogens that are rare,atypical,and mNGS was more likely to detect pathogenic microorganisms in the mechanical ventilation group(82.8%vs 61.3%;P<0.05),while the traditional pathogenic testing showed no significant difference(41.4%vs 22.6%;P=0.076).6.There was a high percentage of fungal infection in immunosuppressed patients.The positive rate of mNGS to detect pathogens can reach 2-3 times that of traditional pathogenic methods(70.9%vs 30.9%;P<0.01).Conclusions:1.mNGS improves sensitivity of pathogen detection in pulmonary infections,which can be used as an effective supplementary method for clinical testing to improve the detection rate of pathogens.2.For patients with ineffective standardized antimicrobial therapy and unexplained causes,combined with rare or atypical pathogen infections,or unclear diagnosis of pathogenic microorganisms,or critically ill patients,especially those with immunosuppression and mechanical ventilation who need to identify the pathogen as soon as possible,it is recommended to apply mNGS detection early.3.The positive result of mNGS has more guiding significance for the treatment strategies of pulmonary infections,especially in patients whose traditional pathogenic tests are negative. |
