A retrospective, multicenter study on the pneumocystis jirovecii pneumonia in critically ill children with non-human immunodeficiency virus using metagenomics next-generation sequencing

Background Pneumocystis jirovecii (PJ) is a life-threatening opportunistic pathogen and an important cause of severe pneumonia in immunocompromised children. Accurate and timely diagnosis is the most important factor for improving pneumocystis jirovecii pneumonia (PCP) related mortality in individuals with non-human immunodeficiency virus (non-HIV) infection. Methods We retrospectively collected clinical data from critically ill children with PJ positive in the metagenomic next-generation sequencing (mNGS) of bronchoalveolar lavage fluid (BALF). Results A total of 59 non-HIV children were included in this study. We classified the children into the PCP group (n = 51) and pneumocystis jirovecii colonization (PCC) group (n = 8). When compared with the PCC group, the PCP group had lower lymphocyte numbers, higher C-reactive protein (CRP), a higher proportion of primary immunodeficiency disease, a higher imaging change of ground-glass opacity on CT scans and higher median mNGS reads number of PJ (all p  < 0.05). The optimal threshold value for discriminating pneumocystis jirovecii infection from colonization appeared to be 556 reads (sensitivity, 77.6%; specificity, 100.0%). Conclusions The BALF mNGS may assist with differentiating between colonization and infection of pneumocystis jirovecii, which needs further investigation.