Treatment of Serratia marcescens meningitis with prolonged infusion of meropenem.

Objective: To describe the use of and cerebral spinal fluid (CSF) penetration of a prolonged infusion meropenem regimen in a patient with Serratia marcescens meningitis.

Case Summary: A 54-year-old female was diagnosed with S. marcescens meningitis associated with an epidural abscess 57 days after surgery for a herniated spinal disk. Meropenem 2000 mg every 8 hours was administered as a prolonged (3 h) infusion for the purpose of optimizing pharmacodynamic exposure. Meropenem concentrations were measured from the patient's blood and CSF (via a lumbar drain). The prolonged infusion regimen resulted in concentrations in both serum and CSF above the meropenem minimum inhibitory concentration (MIC) of 0.047 microg/mL for 100% of the dosing interval. After 6 days of therapy, the patient showed no further signs of infection and was subsequently discharged to a rehabilitation facility. At follow-up, she had completed a 4 week course of the prolonged infused therapy without relapse or adverse events.

Discussion: Gram-negative infections of the central nervous system result in high morbidity and mortality. These infections are often difficult to treat because of poor antibiotic penetration coupled with increasing antibiotic resistance. Although there are 2 other case reports that describe the use of prolonged infusion of meropenem, our patient had a lumbar drain in place, thereby allowing us to collect multiple CSF samples and more accurately assess meropenem exposure at the site of infection. CSF penetration was 6.4% in this patient, resulting in 100% time above the MIC throughout the dosing interval.

Conclusions: In this patient with meropenem-susceptible S. marcescens meningitis, the use of a high-dose prolonged infusion of meropenem resulted in adequate exposure at the site of infection and a successful clinical response.