Community-acquired Listeria monocytogenes meningitis in adults

Background. Listeria monocytogenes is the third most common cause of bacterial meningitis. Methods. We prospectively evaluated 30 episodes of community-acquired L. monocytogenes meningitis, confirmed by culture of cerebrospinal fluid specimens, in a nationwide study in The Netherlands. Outcome was graded using the Glasgow outcome score; an unfavorable outcome was defined as a score of 1-4. Results. We found 30 episodes of L. monocytogenes meningitis. All patients were immunocompromised or > 50 years old. In 19 (63%) of 30 patients, symptoms were present for > 24 h; in 8 patients (27%), symptoms were present for >= 4 days. The classic triad of fever, neck stiffness, and change in mental status was present in 13 (43%) of 30 patients. An individual cerebrospinal fluid indicator of bacterial meningitis was present in 23 (77%) of 30 cases. Gram staining of cerebrospinal fluid samples revealed the causative organism in 7 (28%) of 25 cases. The initial antimicrobial therapy was amoxicillin based for 21 (70%) of 30 patients. The coverage of initial antimicrobial therapy was microbiologically inadequate for 9 (30%) of the patients. The mortality rate was 17% (5 of 30), and 8 (27%) of 30 patients experienced an unfavorable outcome. Inadequate initial antimicrobial therapy was not related to outcome. Conclusions. In contrast with previous reports, we found that patients with meningitis due to L. monocytogenes do not present with atypical clinical features; however, typical cerebrospinal fluid findings predictive for bacterial meningitis might be absent. A high proportion of patients received initial antimicrobial therapy that did not cover L. monocytogenes.