Efficacy and safety of combined intraventricular/intrathecal and intravenous polymyxin B for postsurgical neurosurgical infections due to MDR/XDR-GNB: a retrospective cohort study

Intracranial infections caused by multidrug-resistant or extensively drug-resistant Gram-negative bacteria (MDR/XDR-GNB) represent a significant challenge in neurosurgical critical care, with limited effective treatment options. This study aimed to evaluate the efficacy and safety of intraventricular/intrathecal (IVT/ITH) and intravenous polymyxin B in patients with post-neurosurgical MDR/XDR-GNB intracranial infections, focusing on long-term outcomes and neurotoxicity. This multicenter retrospective cohort study was conducted across seven hospitals in the West China region between December 2019 and June 2021. Patients with culture-confirmed MDR/XDR-GNB intracranial infection were enrolled and divided into two groups based on whether they received IVT/ITH polymyxin B. The primary outcome was 90-day mortality, with secondary outcomes including pathogen clearance rate, neurological status at discharge, and adverse events. Cox proportional hazards models were used to estimate treatment effects. A total of 70 patients were included, with 24 in the IVT/ITH group and 46 in the control group. Baseline characteristics were comparable between groups. The most common pathogens isolated were Acinetobacter baumannii (67.1%), Klebsiella pneumoniae (24.3%), and Pseudomonas aeruginosa (4.3%), with 98.6% of isolates susceptible to polymyxin B. IVT/ITH polymyxin B was associated with significantly improved 90-day survival (adjusted HR 0.50; 95% CI 0.26–0.98) and higher pathogen clearance rates (58.3% vs. 26.7%, p < 0.001). No significant differences in adverse effects, including neurotoxicity, were observed between groups, although a trend toward higher seizure incidence was noted in the IVT/ITH group. IVT/ITH and intravenous administration of polymyxin B significantly improved long-term survival and microbial clearance in patients with MDR/XDR-GNB intracranial infections, with a favorable safety profile. These findings support its use as a promising therapeutic strategy in resource-limited settings where this combined local-systemic regimen is not feasible. This study was approved by the Ethics Committee of West China Hospital, approval number 278.