Relationship between bacterial colonization of external cerebrospinal fluid drains and secondary meningitis: a retrospective analysis of an 8-year period.

Object: A frequent complication of CSF drains is secondary meningitis. This study was designed to assess the predictive value of a positive culture from a CSF drain tip for the development of secondary meningitis.
Methods: The authors conducted a retrospective study of an 8-year period in which patients were treated in a tertiary care hospital in The Netherlands. Patients with positive cultures from CSF drain tips were identified from the microbiology database. Patient charts were reviewed to retrieve demographic, clinical, and laboratory data. Statistical analysis was performed using multivariate logistic regression to determine significant risk factors for the development of secondary meningitis.
Results: A total of 139 patients with positive CSF-drain cultures were included; 72 patients (52%) suffered secondary meningitis at the time of CSF drain removal, or developed it consecutively. Development of secondary meningitis was associated with use of ventricular drains (OR 3.4 vs lumbar drains; 95% CI 1.7-6.8), with age less than 18 years (OR 4.7; 95% CI 1.3-17.3), and with colonization with Staphylococcus aureus (OR 3.1 vs other microorganisms; CI 1.2-8.5). Thirty-two patients (44% of total secondary meningitis) were diagnosed with secondary meningitis 24 hours or more after CSF drain removal; in 13 patients (18%) the diagnosis was made after 48 hours or more.
Conclusions: Positive CSF-drain cultures are strongly associated with development of secondary meningitis. A positive CSF-drain culture may precede clinical symptoms and should therefore be communicated to the treating physician by the microbiological laboratory as soon as possible, and prophylactic antibiotic therapy should be considered.