Empiric Therapy for Suspected Bacterial Meningitis

Introduction to Guideline Recommendations

The Infectious Diseases Society of America recommends vancomycin as part of empiric therapy for suspected bacterial meningitis, which remains a critical concern despite declining resistance rates 1, 2.

Ceftriaxone 2g IV every 12 hours provides essential coverage for the two most common causes of bacterial meningitis in this age group: Streptococcus pneumoniae and Neisseria meningitidis 3, 2.
Vancomycin 15-20 mg/kg IV every 8-12 hours must be added to cover penicillin-resistant and cephalosporin-resistant S. pneumoniae 1, 2.

Dexamethasone 0.15 mg/kg IV every 6 hours should be administered immediately, either 10-15 minutes before or simultaneously with the first antibiotic dose, to reduce mortality and neurological morbidity, particularly in pneumococcal meningitis 1, 2.

The duration of therapy depends on the identified organism: N. meningitidis: 5-7 days 4, S. pneumoniae: 10-14 days 3, 4, and if no organism identified but clinical improvement: 10 days 4.
Antibiotics must be administered within 1 hour of presentation 1, 2, 4.

Never delay antibiotics for imaging or additional procedures, as treatment delay is strongly associated with increased mortality and poor neurological outcomes 1, 2, 4.
Do not use ceftriaxone monotherapy in suspected bacterial meningitis, as vancomycin must be added for adequate pneumococcal coverage given resistance patterns 1.
Do not omit dexamethasone, as it must be given before or with the first antibiotic dose to maximize benefit 1.
Do not add ampicillin reflexively, as it is only indicated for patients ≥50 years or with specific immunocompromising conditions 1, 2, 4.