Novel Use of Metagenomic Next-Generation Sequencing in Diagnosing Streptococcus intermedius Meningitis and Ventriculitis: A Case Report and Literature Review

Background: Streptococcus intermedius is a commensal microflora commonly found in various mucosal sites in the respiratory, gastrointestinal, and genitourinary tracts. It causes invasive suppurative infections including liver and brain abscesses along with thoracic empyema. However, it rarely causes meningitis without abscess formation.

Case presentation: A 56-year-old immunocompetent man who presented with fever and headache. Bacterial meningitis was confirmed using cerebrospinal fluid analysis. Magnetic resonance imaging of the brain revealed leptomeningitis and ventriculitis. However, conventional methods, such as microbiological culture failed to identify the causative pathogens. Metagenomic next-generation sequencing of cerebrospinal fluid revealed the presence of S. intermedius. It allowed us the optimal treatment for him. The patient underwent antibiotic treatment with 6-week duration of ceftriaxone administration accompanied by surgical intervention, resulting in a favorable prognosis.

Conclusion: Herein, we report a rare case of meningitis and ventriculitis caused by S. intermedius using metagenomic next-generation sequencing. The patient recovered well after antibiotic treatment and surgery. We present this rare case and summarize previous studies to remind clinicians that timely identification of the pathogen and optimal treatment are crucial for management of S. intermedius-induced infections.