# Case Commentary: Intraventricular polymyxin B—small steps, big questions

## TL;DR

This commentary discusses the use of intraventricular polymyxin B in treating a rare and severe brain infection, highlighting its effectiveness and raising questions about optimal dosing.

## Contribution

The paper presents two successful cases of intraventricular polymyxin B treatment and raises new questions about dosing and concurrent therapies.

## Key findings

- Intraventricular polymyxin B successfully treated carbapenem-resistant gram-negative ventriculitis in two patients.
- Antibiotic distribution within the ventricles was uneven, and cerebrospinal fluid drainage affected drug concentrations.
- The infection was cured with intraventricular polymyxin B alone, without the need for additional intravenous therapy.

## Abstract

Carbapenem-resistant gram-negative ventriculitis is a life-threatening
infection with limited treatment options. H. Jiang, Y. Hu, J. Cai, J. Zhang,
et al. (Antimicrob Agents Chemother 70:e00943-25, 2026, https://doi.org/10.1128/aac.00943-25)
describe two patients with this condition who were successfully treated with
intraventricular polymyxin B. Their report highlights uneven antibiotic
distribution within the ventricles, the influence of cerebrospinal fluid
drainage on intraventricular drug concentrations, and cure with
intraventricular polymyxin B alone. These findings raise important questions
about optimal intraventricular antimicrobial dosing and whether concurrent
intravenous therapy is needed in healthcare-associated ventriculitis.