Power of Combined Intravenous and Intraventricular Colistin Against Multidrug-Resistant Bacteria in Healthcare-Associated Ventriculitis and Meningitis

Healthcare-associated ventriculitis and meningitis (HAVM) caused by multidrug-resistant (MDR) gram-negative organisms represents a major therapeutic challenge, given the limited penetration of most antibiotics into the cerebrospinal fluid (CSF). Colistin, although active against MDR strains, exhibits poor CSF distribution when administered intravenously alone. We report a case of a 74-year-old man admitted with a cerebellar hemorrhage complicated by hydrocephalus requiring external ventricular drainage. The patient subsequently developed HAVM due to MDR <i>Klebsiella pneumoniae</i>. Initial systemic antibiotic regimens, including intravenous (IV) colistin, failed to control the infection. A combined strategy with IV and intraventricular (IVT) colistin was initiated, resulting in rapid improvement of inflammatory biomarkers and microbiological clearance. However, the patient ultimately died from neurological complications related to the primary hemorrhagic stroke. This case illustrates the potential benefit of combined IV and IVT colistin administration in refractory MDR gram-negative HAVM. While clinical outcomes may be limited by underlying neurological severity, adjunct IVT therapy ensures effective CSF antibiotic concentrations and may improve infection control. Further research is needed to optimize dosing and establish standardized treatment protocols.