Relapsing bacterial meningitis in adults.

Relapsing bacterial meningitis is a rare condition, diagnosed in eight patients between 1981 and 1993 at our institution. These accounted for 3.4% of 234 adult patients with blood and/or cerebrospinal fluid culture-proven bacterial meningitis. A review of the English-language literature from 1966 to the present revealed only five further adult cases of relapsing bacterial meningitis with in-depth case histories. Of these 13 total patients, nine were female and four male, aged 17-61 years. Ten were neurosurgical patients. Gram-negative bacilli, especially Klebsiella species, were the commonest micro-organisms identified for both the initial episode and the relapse of infection. Three patients died in the course of relapse. Four or more weeks of antibiotic therapy may be needed to treat post-surgical patients with Gram-negative bacillary meningitis. Even a normal cerebrospinal fluid study at the end of treatment of bacterial meningitis is not a guarantee of freedom from relapse.