Clinical Characteristics, Treatment, and Outcomes of Veterans with Cerebrospinal Fluid Culture Positive for Gram-Negative Rod Bacteria: A Retrospective Analysis over 18 Years in 125 Veterans Health Administration Hospitals.

Optimal management for patients with bacterial ventriculitis/meningitis due to Gram-negative rods (GNRs) has yet to be well investigated. We assessed the clinical characteristics, treatment, and outcomes of patients with a positive cerebrospinal fluid (CSF) culture for GNRs. We conducted a retrospective cohort study of all patients with a positive CSF culture within the Veterans Health Administration (VHA) system during 2003-2020. Clinical and microbiological characteristics between the true meningitis and contamination groups were compared. Of the 5919 patients with positive CSF cultures among 125 nationwide VHA acute-care hospitals, 297 (5.0%) were positive for GNRs. Among 262 patients analyzed, 156 (59.5%) were assessed as patients with true meningitis, and 106 (40.5%) were assessed as patients with contaminated CSF cultures. Patients with true meningitis had a significantly higher CSF protein (median 168 vs 57 mg/dL, p < 0.001), CSF white blood cell count (median 525 vs 3/µL, p = 0.008) and percentage of neutrophils in CSF (median 88 vs 4%, p < 0.001). Enterobacterales were more common in the true meningitis group, while unidentified GNR or polymicrobial CSF cultures were more common in the contamination group. The all-cause 90-day mortality was 25.0% (39/156) in patients with true meningitis and 10.4% (11/106) in those with contaminated CSF cultures. None of the 11 patients with contaminated CSF cultures who died were considered due to missed meningitis. More than 40% of patients with a positive CSF culture with GNR did not receive treatment without negative consequences. Careful clinical judgment is required to decide whether to treat such patients.