Treatment of Serratia marcescens Meningitis with Prolonged Infusion of Meropenem

OBJECTIVE: To describe the use of and cerebral spinal fluid (CSF) penetration o a prolonged infusion meropenem regimen in a patient with Serratia marcescen meningitis. CASE SUMMARY: A 54-year-old female was diagnosed with S. marcescen 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) o 0.047 μg/mL for 100% of the dosing interval. After 6 days of therapy, the patien 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 o poor antibiotic penetration coupled with increasing antibiotic resistance. Although there are 2 other case reports that describe the use of prolonged infusion o 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. marcescensmenin gitis, the use of a high-dose prolonged infusion of meropenem resulted in adequate exposure at the site of infection and a successful clinical response.