Fusobacterium necrophorum Brain Abscess With Concurrent Nasopharyngeal Detection of Mycoplasma pneumoniae: A Case Report.

Fusobacterium necrophorum is a recognized cause of brain abscesses and has been classically associated with Lemierre syndrome. We report a case of a 17-year-old male patient who presented with seizures, fever, and altered mental status following treatment for sinusitis. Neuroimaging revealed a right frontal lobe abscess requiring surgical drainage. Anaerobic cultures from the abscess fluid grew F. necrophorum, while a respiratory polymerase chain reaction (PCR) panel from a nasopharyngeal swab detected Mycoplasma pneumoniae. Anaerobic cultures also yielded Paenibacillus barengoltzii from a separate soft tissue specimen, though its clinical significance remained uncertain. The patient improved with surgical drainage and targeted antimicrobial therapy. This case highlights concurrent detection of F. necrophorum and M. pneumoniae in a central nervous system infection and underscores the uncertainty regarding the pathogenic role of M. pneumoniae in such presentations.