Brain abscess with bacteremia caused by Listeria monocytogenes in a young woman with immune thrombocytopenic purpura was reported. The clinical features included fever, headache, and left-side weakness. Computed tomography and magnetic resonance imaging of the brain showed a large single abscess at the right frontoparietal area. L. monocytogenes was isolated from a blood culture. The patient promptly received a surgical drainage. Because she had a history of penicillin allergy, and the organism was resistant to ampicillin, she was treated with trimethoprim-sulfamethoxazole (TMP-SMX) alone for 12 months. During a one-year follow-up period, the patient improved and her neurological deficit gradually recovered. This is the first case of listerial brain abscess in Thailand that was successfully treated with TMP-SMX monotherapy and surgical drainage.

Keywords: Listeria monocytogenes, Brain abscess, Trimethoprim-sulfamethoxazole