A case of brain abscess caused by Bacteroides fragilis following intracerebral hemorrhage

An 86-year-old man presented with a 1-week history of headache and visual disturbance. Computed tomography showed intracerebral haemorrhage involving the right occipital lobe, and the patient was admitted for conservative treatment. He developed recurrent episodes of fever secondary to aspiration pneumonia and was treated with antibiotics during each episode. He presented with apraxia 35 days after admission. Diffusion-weighted magnetic resonance imaging performed 41 days after admission showed high signal intensity in the area of haemorrhage with spread into the subdural space and right lateral ventricle. Postoperatively, we diagnosed the patient with a brain abscess based on our surgical findings. Cultures of the surgical specimen and blood yielded Bacteroides fragilis, and the patient was treated with a 6-week course of antibiotic and transferred to a nursing home. This is the first case report that describes identification of the same bacteria in both cultures of a brain abscess and blood. Furthermore, to date, no study has reported B. fragilis as the causative organism of a brain abscess following intracerebral haemorrhage; we present this rare case with a literature review.