Meningitis caused by oral anaerobes detected using mNGS tool: a case report and review of literature

Abstract Background Bacterial meningitis is a central nervous system (CNS) infection disease of the meninges and brain parenchyma caused by the bacteria. Few cases of meningitis related to oral anaerobes have been reported in the literature. Here, we report a case of meningitis in a middle-aged woman, caused by oral anaerobes. Case presentation A 58-year-old woman was admitted to hospital with fever, headache for 21 days and left limb weakness for 2 days. The blood cell counts (11.73 × 109/L), neutrophil counts (9.22 × 109/L) and high-sensitivity C-reactive protein levels (> 5.00 mg/L) were elevated. The brain computerized tomography (CT) scanning indicated the new right thalamus infarct. The brain cranial-enhanced magnetic resonance imaging (MRI) showed the right lateral paraventricular and right thalamic infarct, and abnormal signal in occipital horns of bilateral lateral ventricles were increased. In addition, the brain enhanced nuclear magnetic resonance (NMR) scanning suggested that meninges were thickened and enhanced at the base of the brain, with meningitis changes. The neck CT angiography (CTA) revealed arteriosclerotic changes. The metagenomic next-generation sequencing (mNGS) revealed Eubacterium brachy, Porphyromonas gingivalis, Fusobacterium nucleatum and Torque teno virus in her cerebrospinal fluid (CSF). The patient was diagnosed with purulent meningitis caused by infection of oral anaerobes, and treated with mannitol, ceftriaxone and vancomycin. Her symptoms alleviated. Subsequently, she was transferred to the infectious department and treated with ceftriaxone plus metronidazole (anti-anaerobes) and mannitol (reduce intracranial pressure). Her symptoms improved and currently received rehabilitation treatment. Conclusion We herein report a rare case involving meningitis caused by infection of oral anaerobes. The mNGS can accurately detect the pathogens of infectious diseases.