Antibiotic regimens for meningitis due to susceptible Enterococcus strains* in adults

IV: intravenously.

* For patients failing to respond to systemic antibiotics, intraventricular vancomycin or gentamicin may be useful. Treatment of enterococcal meningitis caused by Enterococcus faecium strains resistant to penicillin, aminoglycosides, and vancomycin is a difficult challenge; intravenous linezolid or intravenous plus intraventricular quinupristin-dalfopristin or daptomycin are reasonable antibiotic choices, although experience with intraventricular administration is limited (refer to the UpToDate topic on infections of central nervous system shunts and other devices). Intravenous and intraventricular daptomycin plus tigecycline as well as intravenous and intraventricular tigecycline have been used as well as high-dose daptomycin plus linezolid or gentamicin.

¶ Penicillin G (18 to 30+ million units per 24 hours) may be used in place of ampicillin for susceptible isolates. Ampicillin-sulbactam may be used in place of ampicillin for treatment of beta-lactamase-producing enterococci, which are very rare. The combination of ampicillin with imipenem is a potential alternative regimen.

Δ Vancomycin (30 mg/kg IV per 24 hours in 2 equally divided doses) is an alternative for patients unable to tolerate beta-lactam agents; goal vancomycin trough is 15 to 20 mcg/mL. An initial vancomycin loading dose of 25 to 30 mg/kg (based on actual body weight, not to exceed 3000 mg) may be used to reduce the time to achieve target trough concentrations for patients with serious infections such as meningitis. In addition, repeat cerebrospinal fluid (CSF) evaluation to evaluate for sterilization and for CSF vancomycin levels is advisable. Rifampin may be added to vancomycin (if susceptible).

◊ No data exist to indicate that single-dose aminoglycoside therapy is superior to divided-dose therapy, but higher serum peaks may result in higher CSF levels. Serum aminoglycoside levels should be monitored (for every 8 hour dosing, gentamicin goal peak 4 to 8 mcg/mL, trough 1 to 2 mcg/mL; streptomycin goal peak 56 to 64 mcg per mL, goal trough <1 mcg/mL). For once-daily dosing, target peak serum concentrations of gentamicin are approximately 15 to 20 mcg/mL, with a trough concentration of less than 1 mcg/mL. Some experts utilize higher doses of gentamicin of up to 7 mg/kg/day with single dose therapy and repeat dosing guided by serum levels and a therapy-specific nomogram^[1]. There is limited guidance on the use of once-daily dosing targets in gram-positive infections; the authors feel it is reasonable to utilize the available data for gram-negative infections in monitoring for aminoglycoside toxicity. If aminoglycosides are administered together with vancomycin, aminoglycoside dose reduction may be warranted to minimize toxicity.