Application Of Metagenomic Next-generation Sequencing In Pathogen Diagnosis Of Children’s Central Nervous System Infection

Objective: In this study,we analyzed the pathogens detected by next-generation sequencing（mNGS）of cerebrospinal fluid and conventional laboratory methods in children with central nervous system（CNS）infection to investigate the diagnostic value of mNGS for the detection of pathogens of nervous system infection in children and provide some reference for clinical diagnosis and treatment.Methods: The relevant data of 42 children with clinical suspected CNS infection in NICU and PICU of Lanzhou University Second Hospital from March 2019 to December 2021 were collected: general conditions,routine laboratory examination results,imaging examinations,mNGS detection reports,clinical medication and disease outcome.The final clinical diagnosis was used as the standard to exclude children with missing general data and a final diagnosis of non-central nervous system infection,37 cases were finally included,one of the children had bacterial and viral infections,so the total sample of infections was 38.Statistical analysis was performed using IBM SPSS26.0 software to compare the difference between mNGS and conventional laboratory methods for the diagnosis of pathogens of CNS infection in children by paired fourfold table chi-square test（Mc Nemar test）or Fisher’s exact test.P<0.05 was considered statistically significant.Results:（1）Among the 38 total infected samples,the positive rate of the pathogens detected by the mNGS detection method was 65.79%,the positive rate of the conventional laboratory methods was 21.05%,and the positive rate of the mNGS was higher than that of the conventional laboratory methods,and the difference was statistically significant（P<0.05）.（2）In children with viral nervous system infection,using the final clinical diagnosis as the standard,the positive rate of the virus（90.00%）detected by mNGS method was higher than that of conventional laboratory methods（50.00%）,and the difference was not statistically significant（P=0.14>0.05）;In children with bacterial nervous system infection,using the clinical final diagnosis as the standard,the positive rate of bacteria（55.56%）detected by mNGS method was higher than that of conventional laboratory methods（11.11%）,and the difference was statistically significant（P<0.05）;In one case of fungal nervous system infection,candida albicans was detected by mNGS,the species-specific read number（SSRN）was 989,the conventional laboratory tests were negative,and the cerebrospinal fluid parameters were better than before after the replacement of antifungal drug treatment,due to the number of cases was only one,statistical analysis could not be performed.（3）According to the time from the date of onset to the time when cerebrospinal fluid was collected and sent for mNGS detection,the shorter the interval,the higher the species-specific read number of mNGS detection.（4）In the cases of empirical use of antibiotics,the positive rate of mNGS detection was higher than that of conventional laboratory methods,and the difference was statistically significant（P<0.05）.Conclusion:（1）The positive rate of pathogens detected by mNGS in children with central nervous system infection is higher than that of conventional laboratory methods,and it is less affected by antibiotics,which can be used for the early diagnosis of pathogens in children with central nervous system infection.（2）The diagnostic ability of mNGS method for pathogens of bacterial central nervous system infection is good,but there are some differences in the diagnostic ability for different pathogens.（3）Early collection and submission of cerebrospinal fluid samples during the course of the disease helps to increase the species-specific read number detected by mNGS.