Intraventricular colistin for multidrug-resistant ventriculitis: the final therapeutic option?

To evaluate the efficacy and safety of intraventricular (IVT) colistin in combination with intravenous therapy for the treatment of multidrug-resistant (MDR) ventriculitis following neurosurgical procedures, and to determine optimal treatment duration and outcomes in the largest single-centre series to date. This retrospective study analysed 46 patients with culture-proven MDR ventriculitis treated at a tertiary care neurosurgical centre between January 2023 and December 2024. All pathogens had a colistin MIC of ≤ 2 µg/mL. IVT colistin (10 mg colistimethate sodium) was administered via external ventricular drain (EVD) for variable durations. Outcomes were compared between patients receiving IVT plus intravenous colistin for ≥ 10 days versus those receiving shorter courses and intravenous colistin alone. The primary outcome was clinical cure; secondary endpoints included infection control timing, mortality, and adverse events. Infection was controlled in 63.6% of cases, with a median time to CSF sterilisation of 7.5 days. Patients receiving IVT and intravenous colistin for ≥ 10 days had significantly higher infection control rates (94% vs. 37%, p = 0.001), lower overall mortality (45% vs. 75%, p = 0.013), and reduced infection-attributable mortality (18.8% vs. 56.3%, p = 0.028) when compared to combined treatment given for less than 10 days. Combined treatment also had better infection control when compared with those that received only intravenous colistin (94% vs. 58%, p = 0.024). The most frequently isolated organism was Acinetobacter baumannii (50%). Adverse effects were limited to acute kidney injury in 4 patients (8.7%), with no neurotoxicity reported. IVT colistin appears to be a safe and effective adjunct to systemic therapy in MDR ventriculitis, particularly when administered for ≥ 10 days. It significantly improves infection control and may reduce infection-related mortality. Given its low neurotoxicity and favourable outcomes in appropriately selected patients, IVT colistin should be considered a cornerstone in managing MDR gram-negative ventriculitis. Prospective multicenter studies are needed to establish standardised treatment protocols.