Pyogenic ventriculitis is a secondary complication of central nervous system (CNS) surgery, trauma, and device implantation [1]. However, primary pyogenic ventriculitis arising from the hematogenous spread of pathogens capable of breaching the blood-brain barrier and seeding the choroid plexus remains rare. As of August 2025, only 36 cases of primary pyogenic ventriculitis have been documented (see Supplementary Table 1).

In cases in which systemic antibiotic therapy is insufficient, intrathecal antibiotic administration should be considered [2]. This can be achieved via two routes: intraventricular injection, typically through an existing ventricular drain, or intralumbar administration via lumbar puncture. Intraventricular administration is more commonly employed in secondary pyogenic ventriculitis, owing to the frequent presence of ventricular drains in these cases. Conversely, in primary cases, systemic antibiotic therapy alone was often administered, and 27 of the 36 cases were managed without surgical intervention. Among the 9 patients who underwent ventricular drainage, only 2 received intraventricular antibiotics. To date, no published case has reported the successful treatment of primary pyogenic ventriculitis using intralumbar antibiotic administration. Herein, we describe the first such case caused by Streptococcus dysgalactiae, which was successfully treated with intralumbar vancomycin in combination with systemic antibiotics.