From the Guidelines
The recommended empiric antibiotic regimen for possible bacterial meningitis in adults is a combination of vancomycin (15-20 mg/kg IV every 8-12 hours, not to exceed 2g per dose) plus a third-generation cephalosporin, either ceftriaxone (2g IV every 12 hours) or cefotaxime (2g IV every 4-6 hours). This combination should be initiated immediately after obtaining blood cultures and preferably after lumbar puncture, but treatment should not be delayed if neuroimaging is required before lumbar puncture. For patients with severe penicillin allergy, meropenem (2g IV every 8 hours) can replace the cephalosporin, or alternatively, chloramphenicol (1g IV every 6 hours) may be used. In patients over 50 years, immunocompromised individuals, or those with other risk factors for Listeria monocytogenes, ampicillin (2g IV every 4 hours) should be added to the regimen 1. Dexamethasone (0.15 mg/kg IV every 6 hours for 2-4 days) should be administered before or with the first dose of antibiotics to reduce inflammatory complications, particularly in pneumococcal meningitis 1.
Key Considerations
- The choice of empiric antibiotic treatment depends on the age of the patient, risk factors for L. monocytogenes, and the regional rate of decreased susceptibility to penicillin and third-generation cephalosporins of S. pneumoniae 1.
- Vancomycin should not be used alone due to doubts about its penetration into adult CSF, especially if dexamethasone has also been given 1.
- A trough vancomycin level of 15-20 mg/L should be aimed for, and the treatment should be optimized according to susceptibility testing once the pathogen has been identified 1.
Special Cases
- For patients with confirmed pneumococcal meningitis who have recovered by day 10, treatment should be stopped 1.
- For patients with confirmed pneumococcal meningitis who have not recovered by day 10,14 days treatment should be given 1.
- For patients with penicillin or cephalosporin resistant pneumococcal meningitis, treatment should be continued for 14 days 1.
References to Guidelines
The recommendations are based on the most recent and highest quality studies, including the ESCMID guideline 1 and the UK Joint Specialist Societies guideline 1.
From the FDA Drug Label
Bacterial Meningitis Adults and children - 150 to 200 mg/kg/day in equally divided doses every 3 to 4 hours The addition of an aminoglycoside with ampicillin may increase its effectiveness against Gram-negative bacteria.
The recommended empiric antibiotic regimen for possible bacterial meningitis is Ampicillin at a dose of 150 to 200 mg/kg/day in equally divided doses every 3 to 4 hours. The addition of an aminoglycoside may enhance the effectiveness of ampicillin against Gram-negative bacteria 2 2.
- Key points:
- Ampicillin dose: 150 to 200 mg/kg/day
- Administration: equally divided doses every 3 to 4 hours
- Consider adding an aminoglycoside for enhanced effectiveness against Gram-negative bacteria
From the Research
Empiric Antibiotic Regimen for Possible Bacterial Meningitis
The recommended empiric antibiotic regimen for possible bacterial meningitis includes:
- A combination of third-generation cephalosporin (such as cefotaxime or ceftriaxone) and vancomycin, as stated in 3 and 4
- The addition of ampicillin if the patient has predisposing factors for infection with Listeria monocytogenes, as mentioned in 4 and 5
- The use of cefotaxime (300 mg/kg per day) or ceftriaxone (100 mg/kg per day) and vancomycin (60 mg/kg per day) as the standard first-line treatment if pneumococcal meningitis cannot be ruled out, as stated in 3
Specific Considerations
- For Neisseria meningitidis or Haemophilus influenzae meningitis, a simple treatment with third-generation cephalosporin can be used, as mentioned in 3
- For Enterobacteriaceae, mainly before 3 months of age, aminoglycosides must be added, as stated in 3
- For listeriosis, amoxicillin for 3 weeks, associated with gentamicin or cotrimoxazole, is recommended, as mentioned in 3
Treatment Duration and Adjustment
- The treatment duration and adjustment should be based on the clinical and bacteriological response, as stated in 3
- A second lumbar puncture may be necessary to adjust the treatment regimen, as mentioned in 3
- The use of dexamethasone to prevent the formation of inflammatory cytokines may be beneficial, as stated in 4