Concordance between blood and cerebrospinal fluid cultures in meningitis

To examine the association between cerebrospinal fluid (CSF) cultures and blood cultures in patients with suspected bacterial or fungal meningitis.

A 5-year retrospective chart review, conducted from April 2012 to January 2017 of consecutive patient encounters with bacterial or fungal organism growth in CSF culture, when a blood culture was also obtained. Patients were excluded if they received antibiotics prior to either lumbar puncture (LP) or blood culture acquisition, or if CSF cultures were positive for common bacterial skin contaminants. Descriptive statistics were used to characterize the dataset.

21 patient encounters met study inclusion criteria. 13 (61.9%; 95% CI 40.2-80.5%) had blood culture growth of the same organism as the CSF culture. 1 patient had a different organism in the blood culture compared to the CSF culture. 6 patients (33.3%, 95% CI 14.8%-56.9%) with positive CSF cultures had negative blood cultures.

Our results suggest an insufficient degree of agreement between CSF and blood culture results. PCR may be a prudent approach in patients requiring immediate antibiotics and delayed LP.