Empiric Treatment for Adult Bacterial Meningitis

Core Empiric Regimen by Patient Population

The American College of Physicians recommends that all adults with suspected bacterial meningitis should immediately receive ceftriaxone 2g IV every 12 hours or cefotaxime 2g IV every 6 hours as the cornerstone of empiric therapy 1, 2, 3
For standard adults (<60 years, immunocompetent), ceftriaxone 2g IV every 12 hours or cefotaxime 2g IV every 6 hours provides coverage for Streptococcus pneumoniae and Neisseria meningitidis, the most common pathogens 1, 3
For adults ≥60 years of age, adding ampicillin/amoxicillin 2g IV every 4 hours to the cephalosporin regimen covers Listeria monocytogenes, which becomes increasingly prevalent in older adults 2, 3

For recent travel to areas with penicillin-resistant pneumococci, adding vancomycin 15-20 mg/kg IV every 12 hours or rifampicin 600mg IV/PO every 12 hours to the cephalosporin is recommended 1, 2, 3
For severe penicillin/cephalosporin allergy (anaphylaxis history), chloramphenicol 25 mg/kg IV every 6 hours is recommended 2, 4

Antibiotic administration must occur within 2 hours of hospital presentation to optimize outcomes and reduce mortality 6, 7, 8
Antibiotics should be given immediately if lumbar puncture is delayed for any reason (CT scan, coagulopathy correction) 1, 2

For Streptococcus pneumoniae identified, continue ceftriaxone 2g IV every 12 hours or cefotaxime 2g IV every 6 hours for 10-14 days 1, 3
For Neisseria meningitidis identified, continue ceftriaxone 2g IV every 12 hours or cefotaxime 2g IV every 6 hours for 5-7 days 1
For Listeria monocytogenes identified, continue ampicillin 2g IV every 4 hours for 21 days 1, 4

The Infectious Diseases Society of America recommends the following durations of therapy: