Fatal meningitis due to Listeria monocytogenes in elderly patients with underlying malignancy

Adult patients with malignancies are considered to be at a high risk for Listeria monocytogenes meningitis. The Microbiology Laboratory's database of the University Hospital of Ioannina, Greece, was searched for cases of L. monocytogenes during the period from January 1990 to December 2002. Listerial meningitis occurred in three patients: one with brain tumour, one with chronic lymphocytic leukaemia, and one with non-Hodgkin's lymphoma. All the patients were older than 70 and they were actively receiving therapy for their malignancy. L. monocytogenes type 4b was isolated from blood and cerebrospinal fluid. All were treated with ampicillin and gentamicin, but they died shortly after the initiation of the treatment. Experience with the three present cases indicated the high mortality rate due to listerial meningitis in this immunosuppressed population. So, listeriosis should be suspected in patients with meningitis and underlying malignancy. Since meningitis due to L. monocytogenes is not distinguishable clinically from other types of bacterial meningitis, it is recommended to cover Listeria in the initial empirical therapy of bacterial meningitis in immunosuppressed patients.