Objective The aim of this study was to evaluate the effectiveness of metagenomic next-generation sequencing (mNGS) for the diagnosis of Pneumocystis jirovecii Pneumonia(PJP) in critically pediatric patients.
Methods Seventeen critically pediatric patients with PJP and 60 patients diagnosed with non-PJP pneumonia who were admitted in pediatric intensive care unit between June 2018 to July 2021 were enrolled. Conventional methods and mNGS for detecting Pneumocystis jirovecii (P. jirovecii) were analyzed. The patients' demographics, comorbidities, laboratory parameters, treatments and 30-days mortality were compared.
Results MNGS showed a satisfying diagnostic performance with a sensitivity of 100% in detecting P. jirovecii compared to Gomori Methenamine silver staining(5.9%) and serum (1,3)-β-D-glucan(86.7%). The diagnostic specifificity of mNGS for PJP was higher than that of serum BDG(56.7%). In PJP cohort, over one thirds' cases had mixed infections. Compared with survivors, non-survivors had higher stringently mapped read numbers(SMRNs) in BALF(P < 0.05), suggesting SMRNs may play a potential role in the severity of response. The detection for P. jirovecii by mNGS both in BALF and blood reached a concordance rate of 100%,and the SMRNs in the BALF were remarkably higher than that in blood samples. Initial antimicrobial treatment was modifified in 88.2% of PJP patients based on the mNGS results.
Conclusion MNGS is a potential and efficient technology in diagnosing PJP and shows a satisfying performance in the detection of co-pathogens. Both blood and BALF samples for mNGS are suggested for the presumptive diagnosis of PJP.