Analysis of Metagenomic Next-generation Sequencing of Cerebrospinal Fluid from Patients with Cryptococcal Meningitis

  Objective  The aim of this study was to evaluate the potential diagnostic value of metagenomic next-generation sequencing(mNGS) for cryptococcus infection in the central nervous system(CNS).

  Methods  The clinical data of 6 patients with cryptococcal meningitis diagnosed with mNGS in Peking Union Medical College Hospital from January 2014 to December 2016 were retrospectively collected, including the routine examinations, the culture of cerebrospinal fluid (CSF), biochemical and cytologic tests, India Ink stain methods, and the sequencing results using BGISEQ-100 sequencing platform to identify the pathogenic microorganisms of CSF.

  Results  The 6 patients'median age was 51 years (range from 26 to 53 years), 4 males and 2 females. None of them had immunodeficiency disease. All had the headache and meningeal irritation, five with fever, and two with diplopia. Lumbar puncture revealed increased opening pressure, slightly increased pleocytosis and protein content, and normal/slightly decreased glucose in all cases. CSF India ink stain was positive in five patients. The antigen of cryptococcal meningitis was positive in 4 patients and the isolation by culture was positive in 2.Cryptococcus specific sequences were detected in all the six patients by mNGS, 5 patients infected with Cryptococcus neoformans and one with Cryptococcus gattii. The identified reads corresponding to Cryptococcus neoformans and Cryptococcus gattii ranged from 108 to 25 361 with genomic coverage rates from 0.19% to 29.00%.

  Conclusion  mNGS may be beneficial to make the diagnosis of cryptococcus infection in CNS, especially for the differential diagnosis of Cryptococcus gattii.