The Application Value Of Metagenomic Second-Generation Sequencing In The Pathogenic Detection Of Patients With Sepsis

Objective:To evaluate the application value of metagenomics next-generation sequencing（mNGS）in the pathogenic detection of patients with sepsis.Compare and analyze the differences between mNGS and blood culture detection methods,and evaluate related indicators that may affect the results of mNGS.Methods:The clinical data of 118 patients with sepsis admitted to the Department of Critical Care Medicine,Shenzhen People’s Hospital from October 2017 to September 2019 were retrospectively analyzed.The pathogen detection rate and coverage of second-generation sequencing and traditional microbial culture of two detection methods in blood samples were compared by the Chi-square χ2 test.And analyzing whether the use of antibiotics before sampling would affects the detection of both.The Chi-square χ2 test and t test were used to analyze and compare the relevant indicators of mNGS positive group and negative group.The Logistic regression analysis was used to explore the risk factors related to mNGS positive detection.Results:1.The pathogenic detection rate of mNGS in blood samples is 35.59%,which was significantly higher than 16.10% of traditional microbial culture（P<0.05）;2.The use of antibiotics before sampling had little effect on the detection rate of mNGS（37.9% vs 29.03%,P=0.374）,and significantly reduced the detection rate of microbial culture（9.19% vs 35.48%,P=0.002）;3.Using blood culture results as the gold standard for bacteremia,the sensitivity,specificity,and Youden index of mNGS are calculated to be 78.95%,72.73%,and 51.68%,respectively;4.The CRP concentration of the mNGS positive group was significantly higher than that of the mNGS negative group（198.32±114.18 vs 141.46±111.68,t=2.532,P=0.013）,while the other infection indexes（WBC,PCT,Neu%）of them were not significant Difference（P>0.05）;In addition,the age,APACHE Ⅱ score,SOFA score,gender,blood type,proportion of septic shock and 28-day mortality of patients with sepsis had not statistically difference between the mNGS positive group and the negative group（P>0.05）;5.Among the risk factors associated with positive mNGS detection,CRP（P=0.021,OR:1.007,95%CI: 1.001-1.012）was the significant variable after removing confounding factors,which could promote the detection of pathogens,while the increase of Neu% might reduce the detection of mNGS（P=0.016,OR: 0.955,95%CI: 0.920-0.991）.Conclusion:The application of mNGS technology can improve the detection rate and coverage of pathogens,and has high sensitivity and specificity,of which could provide a more valuable reference for early targeted anti-infective therapy in patients with sepsis.At the same time,the increase of CRP has a certain promotion significance for the detection of mNGS,and can be used as an indicator of the clinical tendency to choose mNGS methods.