Application Of Metagenomic Next Generation Sequencingin Children With Infectious Diseases In PICU Of A Third Class A Hospital

Objective:To compare the difference between Metagenomic next generation sequencing(m NGS)and traditional methods of pathogen detection,and discuss the application of m NGS in children’s infectious diseases.Methods:choose 2019 June 1 to December 31,2020,a 3 third hospital in urumqi PICU during hospitalization in fever of undeterminder origin children 75 cases,respectively,for suspected infection site sampling and traditional pathogen detection and inspection m NGS pathogens,and then to the diagnosis of two kinds of detection methods effect is summarized and analyzed.Finally,58patients in the infected group were screened out according to the results of the two detection methods,and the basic clinical information of the 58 patients in the infected group was collected.Then,the 58 samples were divided into the detected group(47 cases)and the undetected group(11 cases)according to whether MNGS detected the pathogen,and the peripheral blood and inflammation indexes were measured.To analyze the correlation between pathogens and severity of infectious diseases in children.Results(1)In the 75 included samples,the sensitivity of m NGS was significantly higher than that of culture method(x~2=19.053,P<0.01).There was no significant difference between the specificity of m NGS and the culture method(x~2=4.167,P=0.041).The number of days in hospital in the undetected group was higher than that in the detected group(t=4.227,P<0.05).Among the samples,58 cases(77.33%)were in the infected group,while the remaining 17 cases(22.67%)were in the non-infected group.In the infected group,bronchoalveolar lavage fluid was the most common(27/58),followed by blood(20/58)and cerebrospinal fluid(11/58).Univariate analysis showed that the peripheral blood count and inflammation indexes in the detected group were significantly higher than those in the undetected group(t values were-8.84,-4.724,-4.335,-4.335,respectively,all P<0.05).(2)The positive detection rate of m NGS for human herpes virus in children is higher than that of blood antibody detection(P<0.05).(3)In the data of our hospital,human herpesvirus(18.75%)was the top three pathogens detected,Mycoplasma pneumoniae(15.63%)was the second pathogen detected,and Haemophilus influenzae(12.50%)was the third pathogen.Concomitant fungal infections were detected in 2 children with the underlying and more severe disease,Anaerobic bacteria infection was detected in the bronchoalveolar lavage fluid of a child with recurrent pulmonary abscess,and Mycobacterium tuberculosis complex group was detected in the cerebrospinal fluid of a suspected tuberculous encephalopathy case.(4)Data In the case data,the most common positive pathogens in the bronchoalveolar lavage fluid were Mycoplasma pneumoniae(7cases)and Streptococcus pneumoniae(4cases),Human herpesvirus was the most common pathogen in cerebrospinal fluid and whole blood samples(5 and 6 cases,respectively).(5)In the diagnosis of bacterial,viral and atypical pathogens,the positive detection rate of m NGS was significantly higher than that of traditional detection methods.(6)Gram-negative bacteria were more common in bacterial infection,and the pathogens were mainly,Acinetobacter baumannii,Klebsiella pneumoniae,Pseudomonas aeruginosa and Haemophilus influenzae.The main pathogen of viral infection is human herpesvirus,the most common being human herpesvirus type 1(herpes simplex virus type 1),type 4(Epstein-Barr virus),and type 5(cytomegalovirus),respectively.Pneumocystis was the most common fungal infection.Conclusion(1)The positive detection rate of m NGS in the diagnosis of infectious diseases is generally better than that of traditional methods,and it is more significant in the diagnosis of viruses,atypical pathogens and mixed infections.And because of the traditional detection method is relatively limited,m NGS for some unknown pathogens or suspected cases with clinical diagnosis of infection,although the gold standard for diagnosing infectious diseases remains traditional tests,m NGS have not been completely replaced,but can assist in the laboratory as complement of etiology detection,used in combination can improve the detection rate of pathogen of infectious diseases,in order to achieve quick treatment,the purpose of accurate medication.(2)m NGS technology improves the detection rate of atypical pediatric pathogens such as human herpesvirus and mixed infections.