AUTHOR=Liu Li , Yuan Mingjuan , Shi Yi , Su Xin 

TITLE=Clinical Performance of BAL Metagenomic Next-Generation Sequence and Serum (1,3)-β-D-Glucan for Differential Diagnosis of Pneumocystis jirovecii Pneumonia and Pneumocystis jirovecii Colonisation

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=11

YEAR=2021

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2021.784236

DOI=10.3389/fcimb.2021.784236

ISSN=2235-2988

ABSTRACT=<sec><title>Background</title><p>Differentiating <italic>Pneumocystis jirovecii</italic> infection from colonisation is crucial for appropriate therapy administration. In this study, we evaluated the performance of bronchoalveolar lavage fluid (BAL) metagenomic next-generation sequencing (mNGS) and serum 1,3-β-D-glucan (BDG) tests in differentiating colonisation and infection with <italic>P. jirovecii.</italic></p></sec><sec><title>Methods</title><p>From January 2018 to March 2021, 47 patients were enrolled in this study at the Hunan Provincial People’s Hospital. The final diagnosis was used as a reference, and cases were classified into the <italic>P. jirovecii</italic> pneumonia (PJP) group or the <italic>P. jirovecii</italic> colonisation (PJC) group. Clinical data were recorded. The performances of mNGS and BDG were compared.</p></sec><sec><title>Result</title><p>The fungal load significantly differed between patients with PJP and PJC, with median reads of 3,215.79 ± 1,797 <italic>vs</italic>. 5.61 ± 0.88 in the PJP and PJC groups, respectively (<italic>P</italic> &lt; 0.0001). BDG also significantly differed between the two groups, with a median titre of 233.60 ± 39.65 pg/ml in the PJP group and 68.48 ± 19.21 pg/ml in the PJC group (<italic>P =</italic> 0.0006). The area under the curve was 0.973 (95%CI: 0.868–1.007) for mNGS of the BAL and 0.879 (95%CI: 0.769–0.989) for the serum BDG. The optimal threshold value for discriminating <italic>P. jirovecii</italic> infection from colonisation appeared to be 14 reads (sensitivity, 83.3%; specificity, 95.7%; positive likelihood ratio, 19.2) and BDG = 88.6 pg/ml (sensitivity, 79.2%; specificity, 92.9%; positive likelihood ratio, 18.2). No correlation between mNGS reads and the BDG titre was found in mNGS-positive patients (<italic>r</italic><sup>2</sup> = 0.0076, <italic>P</italic> = 0.583). The levels of lactate dehydrogenase and C-reactive protein were significantly higher in the PJP group than in the PJC group.</p></sec><sec><title>Conclusion</title><p>BAL mNGS and serum BDG are useful adjunct tests that can assist with differentiating between colonisation and infection of <italic>P. jirovecii</italic>.</p></sec>