Brain abscess due to Listeria monocytogenes -: Five cases and a review of the literature

Brain abscess is a relatively uncommon form of listerial central nervous system infection. We describe 5 patients with listerial brain abscess, including the first 3 cases of listerial brain abscess described in cardiac transplant recipients, and review 34 cases from the literature. Most patients had significant underlying illnesses, including conditions with altered cell-mediated immunity. The most common presenting symptoms were focal neurologic deficits, mental status changes, and fever. Blood cultures were commonly positive; however, cerebrospinal fluid cultures were positive in only one-third of patients. Most patients presented with a single, monobacterial brain abscess, and one-fifth of the patients had subcortical gray matter involvement. Various antilisterial antibiotics were used, most commonly ampicillin plus an aminoglycoside. Six deaths were attributed to listerial brain abscess in this series, and none of these patients had early neurosurgical intervention. Many patients were successfully treated with antibiotics alone; however, nearly half of the patients required surgical drainage of the abscess. Listeria monocytogenes infection should be included in the differential diagnosis of any patient with altered cell-mediated immunity who presents with a brain abscess. The central nervous system may be the only site of Listeria involvement, and the diagnosis should be considered in any patient who presents with focal neurologic signs, mental status changes, and Listeria monocytogenes bacteremia. Successful treatment often requires the early involvement of a neurosurgical team in addition to antilisterial antibiotics.