Metagenomic detection of central nervous system infections missed by conventional testing.

Abstract

Community-acquired infectious meningoencephalitis is associated with high rates of mortality and morbidity, compounded by limited access to diagnostic resources. The current study assessed acute central nervous system (CNS) infections in patients with meningoencephalitis enrolled in a hospital-based diagnostic surveillance study in São Paulo, Brazil. Cerebrospinal fluid (CSF) was collected from 600 subjects between March 2018 and November 2019 and initially screened for a broad range of pathogens according to a local diagnostic algorithm. Standard microbiological and molecular diagnostic methods were applied. Metagenomic sequencing was used as a complementary approach to investigating etiology in cases where no pathogen was initially identified. Standard testing identified infectious etiologies in 292 cases (48.6%), with 227 (77.7%) confirmed as viral infections, predominantly caused by enteroviruses (n=144) and herpesviruses (n=40). Non-viral agents were identified in 65 cases (22.3%). Metagenomic sequencing (mNGS) of 279 out of 308 undiagnosed cases revealed several additional potential etiologies, including Parvovirus B19, Toxoplasma gondii, Picobirnavirus, other enterovirus species and Vesivirus, the latter being associated with CNS infection for the first time. These findings underscore the complexity of CNS infections and highlight the potential of metagenomics to improve diagnostic accuracy, inform treatment strategies, and support efforts to address future pandemics.