What are the recommended antibiotics for treating bacterial meningitis?

From the Guidelines

The recommended antibiotics for bacterial meningitis typically include a combination of vancomycin plus a third-generation cephalosporin such as ceftriaxone or cefotaxime as empiric therapy. For adults, vancomycin is dosed at 15-20 mg/kg IV every 8-12 hours, while ceftriaxone is given at 2g IV every 12 hours. Cefotaxime can be used at 2g IV every 4-6 hours. This combination provides coverage against the most common causative organisms: Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae.

Key Considerations

• Treatment should be initiated immediately after obtaining blood cultures and cerebrospinal fluid, without waiting for results, as delays increase mortality 1.
• For patients with penicillin allergies, meropenem (2g IV every 8 hours) may be substituted.
• Once the pathogen is identified, therapy can be narrowed.
• Treatment duration is typically 7-14 days depending on the causative organism, with longer courses for Listeria (ampicillin 2g IV every 4 hours for 21 days) and gram-negative bacilli 1.
• Dexamethasone (0.15 mg/kg IV every 6 hours for 2-4 days) should be considered, especially for pneumococcal meningitis, as it reduces inflammation and improves outcomes when given before or with the first antibiotic dose 1.

Patient Groups and Treatment

• Neonates <1 month old: Amoxicillin/ampicillin/penicillin plus cefotaxime, or amoxicillin/ampicillin plus an aminoglycoside 1.
• Age 1 month to 18 years: Cefotaxime or ceftriaxone plus vancomycin or rifampicin 1.
• Age >18 and <50 years: Cefotaxime or ceftriaxone plus vancomycin or rifampicin 1.
• Age >50 years, or Age >18 and <50 years plus risk factors for Listeria monocytogenes: Cefotaxime or ceftriaxone plus vancomycin or rifampicin plus amoxicillin/ampicillin/penicillin G 1.

From the FDA Drug Label

MENINGITIS Caused by Haemophilus influenzae, Neisseria meningitidis or Streptococcus pneumoniae Bacterial Meningitis caused by E. coli, Group B Streptococci, and other Gram-negative bacteria (Listeria monocytogenes, N. meningitidis)

The recommended antibiotics for treating bacterial meningitis are:

• Ceftriaxone for infections caused by Haemophilus influenzae, Neisseria meningitidis, or Streptococcus pneumoniae 2
• Ampicillin for infections caused by E. coli, Group B Streptococci, and other Gram-negative bacteria (Listeria monocytogenes, N. meningitidis) 3

From the Research

Recommended Antibiotics for Bacterial Meningitis

The following antibiotics are recommended for treating bacterial meningitis:

• Ceftriaxone or cefotaxime as empirical treatment, due to their effectiveness against common causative bacteria such as Streptococcus pneumoniae, Neisseria meningitis, and Haemophilus influenzae 4
• Meropenem as an alternative for penicillin- and cephalosporin-resistant pneumococcal meningitis, although more clinical data are required to confirm its effectiveness 5
• Vancomycin in combination with ceftriaxone or rifampicin for highly cephalosporin-resistant Streptococcus pneumoniae strains 6
• Aminopenicillin and aminoglycoside for Listeria monocytogenes, which remains fully susceptible to aminopenicillin 4

Treatment Considerations

When selecting antibiotics for bacterial meningitis, consider the following:

• The suspected causative bacterium and its antimicrobial susceptibility pattern 4
• The need for rapid CSF sterilization to reduce mortality and morbidity 4
• The potential for antibiotic resistance, allergy, or contraindications, which may require the use of alternative antibiotics or combinations 4
• The importance of achieving high bactericidal titers in the cerebrospinal fluid, as seen with ceftriaxone 7

Specific Antibiotic Regimens

Some studies have investigated specific antibiotic regimens for bacterial meningitis, including:

• Ceftriaxone alone or in combination with vancomycin or rifampicin for pneumococcal meningitis 6
• Ceftriaxone as a single daily dose for the treatment of bacterial meningitis, with CSF concentrations remaining above the MIC of the pathogenic bacteria for an extended period 8
• Ceftriaxone or cefotaxime in combination with ampicillin for suspected bacterial meningitis in adults, to cover Listeria monocytogenes until CSF culture results are available 7