To assess the meningeal penetration of cefazolin and cloxacillin in individuals treated for methicillin-susceptible staphylococcal meningitis.

We retrospectively identified individuals treated for Staphylococcus meningitis with measurements of cefazolin or cloxacillin concentrations in cerebrospinal fluid (CSF) using a validated assay of liquid chromatography coupled with mass spectrometry at the Nantes University Hospital between January 2009 and October 2019. Staphylococcus meningitis was defined by a compatible clinical presentation and a microbiological confirmation (positive CSF culture or positive specific PCR). Medical charts were retrospectively reviewed to collect microbiological and clinical data, and to assess therapeutic success.

Among the 17 included individuals, eight (47%) were treated with cefazolin and nine (53%) with cloxacillin. Median daily dosages of cefazolin and cloxacillin were 8 g (range 6-12 g) and 12 g (range 10-13 g), respectively. Cefazolin and cloxacillin were mainly administered by continuous infusion. Eleven individuals (65%) were men, median (interquartile range (IQR)) age was 54 years (50; 70), 14 (82%) had postoperative meningitis and 3 (18%) had haematogenous meningitis. Median (IQR) antibiotic CSF concentrations were 2.8 mg/L (2.1; 5.2) and 0.66 mg/L (0.5; 0.9) for cefazolin and cloxacillin groups, respectively. Cloxacillin was discontinued in two individuals for therapeutic failure.

Patients with staphylococcal meningitis treated with high-dose continuous intravenous infusion of cefazolin achieved therapeutic concentrations in CSF. Cefazolin appears to be a therapeutic candidate that should be properly evaluated in this indication.