Diagnostic Performance of Metagenomic Next-Generation Sequencing in Central Nervous System Cryptococcosis Using Cerebrospinal Fluid

Xuan Zhang,1 Yaqing Lin,2 Huixin Chen,1 Jianhua Hu,1 Hong Zhao,1 Meifang Yang,1 Dongsheng Han3– 5 1State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, People’s Republic of China; 2Shulan (Hangzhou) Hospital Affiliated to Zhejiang Shuren University Shulan International Medical College, Hangzhou, Zhejiang, People’s Republic of China; 3Department of Laboratory Medicine, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, People’s Republic of China; 4Key Laboratory of Clinical in vitro Diagnostic Techniques of Zhejiang Province, Hangzhou, Zhejiang, People’s Republic of China; 5Institute of Laboratory Medicine, Zhejiang University, Hangzhou, Zhejiang, People’s Republic of ChinaCorrespondence: Dongsheng Han, Centre of Clinical Laboratory, First Affiliated Hospital, College of Medicine, Zhejiang University, 79 Qingchun Road, Hangzhou, 310003, People’s Republic of China, Tel +86-571-87236394, Fax +86-571-87236394, Email hands@zju.edu.cnPurpose: Metagenomic next-generation sequencing (mNGS) has been widely used to diagnose infectious diseases. However, there are few studies on its diagnostic performance in the central nervous system (CNS) cryptococcosis. This study examined the diagnostic efficacy of mNGS in identifying Cryptococcus spp. in cerebrospinal fluid (CSF) samples.Patients and Methods: From March 2021 to March 2023, 290 patients with suspected CNS infection were recruited from the First Affiliated Hospital, School of Medicine, Zhejiang University, and 74 patients were ultimately included in the study. Lastly, 22 patients with CNS cryptococcosis were included. Of these patients, 25 CSF samples were enrolled. The diagnostic performance of conventional assays [including India ink, cryptococcal antigen (CrAg) testing, and culture] and mNGS was evaluated for CNS cryptococcosis.Results: In the 25 samples collected, the coincidence rates of mNGS with India ink, CrAg, and culture were 64.0% (16/25), 80.0% (20/25), and 80.0% (20/25), respectively. Without antifungal drug exposure, the coincidence rates were increased to 66.7% (10/15), 100.0% (15/15), and 93.3% (14/15), respectively. The coincidence rates after antifungal therapy were all decreased to 60.0% (6/10), 50.0% (5/10), and 60.0% (6/10), respectively. Moreover, in the 25 samples, the sensitivity of mNGS reached 80.0%, and of India ink, CrAg testing, and culture were 68.0, 100.0, and 60.0%, respectively. The mNGS showed an excellent positive rate (100.0%) in the 15 samples collected without antifungal drug exposure, which was significantly higher than the antifungal drug-exposed group (n = 10) (50.0%) (P = 0.005). The reads of Cryptococcus spp. before antifungal therapy were significantly higher than after it (median, 25,915 vs 2, P = 0.008).Conclusion: mNGS is an effective tool for diagnosing CNS cryptococcosis using CSF; however, its sensitivity decreases considerably in patients who have been effectively treated with antifungal drugs.Keywords: metagenomic next-generation sequencing, central nervous system cryptococcosis, cerebrospinal fluid, invasive fungal infection