Ruptured intraventricular brain abscesses due to Fusobacterium nucleatum with obstructive hydrocephalus: illustrative case

BACKGROUND Fusobacterium spp. are strictly anaerobic microorganisms and normal flora of the oropharyngeal, gastrointestinal, and female genital tracts. It is commonly associated with periodontal disease, pharyngitis, mastoiditis, and tonsillitis, with a tendency to abscess formation. OBSERVATIONS The authors report a case of brain abscesses complicated by ventriculitis and obstructive hydrocephalus caused by Fusobacterium nucleatum of suspected odontogenic source. While repeated bacterial cultures remained negative, the isolate was identified using bacterial sequencing. LESSONS Empirical antimicrobial coverage for F. nucleatum should be considered in patients presenting with brain abscess. Genetic bacterial sequencing utilizing 16S ribosomal RNA molecular diagnostic testing may assist in microorganism identification to guide antimicrobial therapy.