Etiological Study Of Refractory Pneumonia In Children Based On Metagenomic Sequencing

Objective: The similarities and differences between metagenomic next-generation sequencing(mNGS)and traditional pathogen detection results were compared,and the etiological characteristics of refractory pneumonia(RF)were analyzed to provide reference for clinical diagnosis and treatment.Methods: The pathogens of refractory pneumonia in children admitted to Guilin People’s Hospital from January 2022 to January 2023 were retrospectively analyzed.Blood samples were taken to detect virus and atypical pathogens within 2 hours after admission.bronchoalveolar lavage fluid(BALF)was collected by tracheoscope and divided into 2 parts.One part was sent to our hospital for traditional etiological testing(including staining and culture)as the control group,and the other part was sent to a third-party testing institution for pathogenic microbial metagenomic sequencing(DNA)as the experimental group.The pathogen results of the two groups were collected,and the positive rate,consistency and clinical coincidence rate of the pathogens in the two groups were compared,and the pathogen distribution of refractory pneumonia was analyzed.Results: 1.A total of 45 cases were collected,including 25 males and 20 females.The mean age was 31.2 months and the median was 14.0(5.3,53.3)months.Body weight(12.28±7.05)kg;The median course of disease was 17.5(8.5,34.3)days;Hospitalization days(9.5±3.3);Use of antibiotics before hospitalization 77.78%(35/45);The utilization rate of antibiotics before tracheoscopy was 93.33%(42/45),and the replacement rate after tracheoscopy was 53.33%(24/45).2.The positive rate of bacteria and fungi in mNGS group was significantly higher than that in control group(66.67%vs26.67%,100%vs0%,P<0.05).mNGS and control group showed moderate consistency of viruses and atypical pathogens(The Kappa values were 0.78 and 0.45,respectively),and poor consistency of bacteria(Kappa value was 0.15).The clinical coincidence rate of bacteria and fungi in mNGS group was higher than that in control group(80.77%vs23.08%,100%vs0%,P<0.05).Antibiotics were modified in 14 cases(56%)according to mNGS results.3.Pathogen distribution of refractory pneumonia: Among the 45 children,38(84.44%)were pathogenic positive,30(66.67%)had 52 bacterial infections(39 gram-positive strains and 13 Gram-negative strains),9(20.00%)had 11 viral infections,13(28.89%)had 13 atypical pathogen infections,and 4(8.89%)had4 fungal infections.There were 26 cases(57.78%)of mixed infection and 8cases(30.77%)of bacteria and atypical pathogens.The age of infection was mainly in infancy.Conclusion: 1.Compared with traditional pathogen detection,the positive rate of bacteria/fungi detected by mNGS(DNA)is higher and the clinical coincidence rate is higher.2.The main pathogens of refractory pneumonia are bacterial infection,followed by atypical pathogens and viruses.The bacterial infection was dominated by gram-positive bacteria,mainly streptococcus and staphylococcus.The gram-negative bacteria was no obvious dominant strain.Cytomegalovirus is the main virus(DNA)infection.The main infection types were mixed infection,with bacteria and atypical pathogens being common.3.mNGS has a good guiding significance for clinical antibiotic selection.If conditions permit,it is suggested to improve the detection rate of mNGS as soon as possible,so as to provide the etiological basis for the treatment plan and carry out targeted treatment.