Application of Metagenomic Next-Generation Sequencing to Diagnose Pneumocystis jirovecii Pneumonia in Kidney Transplantation Recipients

BACKGROUND: Pneumocystis jirovecii pneumonia (PJP) is one of the common opportunistic infections diagnosed in kidney transplantation recipients. It is difficult to identify early by use of classic tools such as Grocott-Gomori stains and polymerase chain reaction (PCR). Metagenomic next-generation sequencing (mNGS) is accurate, unbiased, and sensitive, and is promising in PJP diagnosis. MATERIAL/METHODS: Data on kidney transplantation patients diagnosed with PJP were retrospectively analyzed. The sensitivity and specificity of different tools such as mNGS, laboratory tests, and Grocott-Gomori stains for PJP diagnosis were compared. All recipients were treated with trimethoprim-sulfamethoxazole (TMP-SMX). RESULTS: There were a total of 12 kidney transplantation recipients diagnosed with PJP based on mNGS in our center from January 01, 2020 to October 27, 2020. Highly variable numbers of sequence reads for P. jiroveci (19 to 1041285) showed diagnostic significance. Bronchoalveolar lavage fluid (BALF) samples were tested by Grocott-Gomori staining, with only 6 of 11 (54.5%) positive. Other routine laboratory tests like routine blood tests, blood biochemistry, procalcitonin (PCT), immune function, (1,3)-β-d-glucan (BG), serum galactomannan (GM), and C-reactive protein (CRP) showed even lower efficacy. TMP-SMX appeared to be the ideal therapy for kidney transplantation recipients with PJP. CONCLUSIONS: mNGS has utility in the diagnosis of PJP and mixed infections in kidney transplantation recipients, and TMP-SMX could be the ideal therapeutic drug for kidney transplantation recipients suffering from PJP.