A Rare Case of Meningitis: Can Cellulosimicrobium cellulans Cause Meningitis in a Non-immunocompromised Person?

Infections with Gram-positive soil-dwelling <i>Cellulosimicrobium cellulans</i> bacterium are sporadic. Rarely, do patients with indwelling medical devices or those who suffer from immunosuppression get infected by this pathogen. However, based on routine clinical and laboratory procedures, it is hard to distinguish between the meningitis caused by <i>C. cellulans</i> and that from other bacteria. Here, we report a unique case of <i>C. cellulans</i> infection in a 37-year-old immunocompetent man presenting with meningitis associated with encephalopathy and headache. He presented with severe headaches, altered sensorium, reduced sleep, photophobia, and restlessness, with a feeling of impending doom, but with no neck rigidity and fever. Trans-axial T1 and T2/FLAIR head MRI showed diffused cerebral edema, with bilateral high frontoparietal sulcal enhancement, hyperintensity along the right posterior insula-temporal region, and left parietal deep white matter. Lumbar puncture CSF examination indicated bacterial meningitis, and <i>C. cellulans</i> was identified on culture. The patient was administered intravenous ceftriaxone for seven days and dexamethasone for three days. A follow-up lumbar puncture CSF examination showed no signs of the pathogen, indicating its eradication. To our knowledge, this is the first case of <i>C. cellulans</i> causing meningitis in an otherwise healthy man with no history of indwelling medical devices or immunosuppression. This rare case of meningitis suggests that <i>C. cellulans</i> can infect healthy humans and cause meningitis.