Bacterial Meningitis Organism-Specific Therapy 

Updated: May 06, 2020
Author: Darvin Scott Smith, MD, MSc, DTM&H; Chief Editor: Michael Stuart Bronze, MD 

Specific Organisms and Therapeutic Regimens

Organism-specific therapeutic regimens for bacterial meningitis are outlined below, including those for Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis, Listeria monocytogenes, Streptococcus agalactiae, Enterobacteriaceae organisms, and Pseudomonas aeruginosa.[1, 2, 3, 4]

Streptococcus pneumoniae meningitis

Table 1. Primary and alternative antimicrobial agents for Streptococcus pneumoniae meningitis. (Open Table in a new window)

Susceptibility

Primary Therapy

Alternative Therapy

Penicillin MIC ≤0.06 mcg/mL

Penicillin or ampicillin

Ceftriaxone or cefotaxime

Penicillin MIC ≥0.12 mcg/mL

Penicillin or ampicillin

Ceftriaxone or cefotaxime

Ceftriaxone or cefotaxime MIC < 1 mcg/mL

Ceftriaxone or cefotaxime

Cefepime, meropenem

Ceftriaxone or cefotaxime MIC ≥1 mcg/mL

Vancomycin plus a ceftriaxone or cefotaxime

Fluoroquinolone

Table 2. Dosages of antimicrobial therapy for S pneumoniae meningitis. (Open Table in a new window)

Antimicrobial Agent

Adults: Total Daily Dose (Dose Interval in Hours)

Pediatrics: Total Daily Dose (Dose Interval in Hours)

Ampicillin

12 g (4)

300-400 mg/kg (6)

Cefepime

6 g (8)

150 mg/kg (8)

Cefotaxime

8-12 g (4-6)

300 mg/kg (6-8)

Ceftriaxone

4 g (12)

100 mg/kg (12-24)

Fluoroquinolone

Varies by specific drug

Varies by specific drug

Meropenem

6 g (8)

120 mg/kg (8)

Penicillin G

24 million units (4)

300,000 units/kg (4-6)

Vancomycin

30-60 mg/kg (8-12)

60 mg/kg (6)

Haemophilus influenzae meningitis

Table 3. Primary and alternative antimicrobial agents for Haemophilus influenzae meningitis. (Open Table in a new window)

Susceptibility

Primary Therapy

Alternative Therapy

Beta-lactamase-negative

Ampicillin

Ceftriaxone or cefotaxime, cefepime, fluoroquinolone, aztreonam

Beta-lactamase-positive

Ceftriaxone or cefotaxime

Cefepime, fluoroquinolone, aztreonam

Table 4. Dosages of antimicrobial therapy for H influenzae meningitis. (Open Table in a new window)

Antimicrobial Agent

Adults: Total Daily Dose (Dose Interval in Hours)

Pediatrics: Total Daily Dose (Dose Interval in Hours)

Ampicillin

12 g (4)

300-400 mg/kg (6)

Aztreonam

6-8 g (6-8)

120 mg/kg (6-8)

Cefepime

6 g (8)

150 mg/kg (8)

Cefotaxime

8-12 g (4-6)

300 mg/kg (6-8)

Ceftriaxone

4 g (12)

100 mg/kg (12-24)

Fluoroquinolone

Varies by specific drug

Varies by specific drug

Neisseria meningitidis meningitis

Table 5. Primary and alternative antimicrobial agents for Neisseria meningitidis meningitis. (Open Table in a new window)

Susceptibility

Primary Therapy

Alternative Therapy

Penicillin MIC < 0.1 mcg/mL

Penicillin G or ampicillin

Ceftriaxone or cefotaxime

Penicillin MIC 0.1 to 1.0 mcg/mL

Ceftriaxone or cefotaxime

Fluoroquinolone, meropenem

Table 6. Dosages of antimicrobial therapy for N meningitidis meningitis. (Open Table in a new window)

Antimicrobial Agent

Adults: Total Daily Dose (Dose Interval in Hours)

Pediatrics: Total Daily Dose (Dose Interval in Hours)

Ampicillin

12 g (4)

300-400 mg/kg (6)

Cefotaxime

8-12 g (4-6)

300 mg/kg (6-8)

Ceftriaxone

4 g (12)

100 mg/kg (12-24)

Fluoroquinolone

Varies by specific drug

Varies by specific drug

Meropenem

6 g (8)

120 mg/kg (8)

Penicillin G

24 million units (4)

300000 units/kg (4-6)

Listeria monocytogenes meningitis

Table 7. Dosages of antimicrobial therapy for Listeria monocytogenes meningitis. (Open Table in a new window)

Primary Therapy

Alternative Therapy

Ampicillin or penicillin G

Trimethoprim-sulfamethoxazole

Table 8. Dosages of antimicrobial therapy for L monocytogenes meningitis. (Open Table in a new window)

Antimicrobial Agent

Adults: Total Daily Dose (Dose Interval in Hours)

Pediatrics: Total Daily Dose (Dose Interval in Hours)

Ampicillin

12 g (4)

300-400 mg/kg (6)

Penicillin G

24 million units (4)

300000 units/kg (4-6)

Trimethoprim-sulfamethoxazole

10-20 mg/kg (6-12)

10-20 mg/kg (6-12)

Streptococcus agalactiae meningitis

Table 9. Dosages of antimicrobial therapy for Streptococcus agalactiae meningitis. (Open Table in a new window)

Primary Therapy

Alternative Therapy

Ampicillin or penicillin G

Ceftriaxone or cefotaxime

Table 10. Dosages of antimicrobial therapy for S agalactiae meningitis. (Open Table in a new window)

Antimicrobial Agent

Adults: Total Daily Dose (Dose Interval in Hours)

Pediatrics: Total Daily Dose (Dose Interval in Hours)

Ampicillin

12 g (4)

300-400 mg/kg (6)

Cefotaxime

8-12 g (4-6)

300 mg/kg (6-8)

Ceftriaxone

4 g (12)

100 mg/kg (12-24)

Penicillin G

24 million units (4)

300000 units/kg (4-6)

Enterobacteriaceae organisms

Table 11. Dosages of antimicrobial therapy for Enterobacteriaceae organisms. (Open Table in a new window)

Primary Therapy

Alternative Therapy

Ceftriaxone or cefotaxime

Aztreonam, fluoroquinolone, meropenem, trimethoprim-sulfamethoxazole, ampicillin

Table 12. Dosages of antimicrobial therapy for Enterobacteriaceae organisms. (Open Table in a new window)

Antimicrobial Agent

Adults: Total Daily Dose (Dose Interval in Hours)

Pediatrics: Total Daily Dose (Dose Interval in Hours)

Ampicillin

12 g (4)

300-400 mg/kg (6)

Aztreonam

6-8 g (6-8)

120 mg/kg (6-8)

Cefotaxime

8-12 g (4-6)

300 mg/kg (6-8)

Ceftriaxone

4 g (12)

100 mg/kg (12-24)

Fluoroquinolone

Varies by specific drug

Varies by specific drug

Meropenem

6 g (8)

120 mg/kg (8)

Trimethoprim-sulfamethoxazole

10-20 mg/kg (6-12)

10-20 mg/kg (6-12)

Pseudomonas aeruginosa meningitis

Table 13. Dosages of antimicrobial therapy for Pseudomonas aeruginosa meningitis. (Open Table in a new window)

Primary Therapy

Alternative Therapy

Cefepime or ceftazidime

Aztreonam, ciprofloxacin, meropenem

Table 14. Dosages of antimicrobial therapy for P aeruginosa meningitis. (Open Table in a new window)

Antimicrobial Agent

Adults: Total Daily Dose (Dose Interval in Hours)

Pediatrics: Total Daily Dose (Dose Interval in Hours)

Aztreonam

6-8 g (6-8)

120 mg/kg (6-8)

Cefepime

6 g (8)

150 mg/kg (8)

Ceftazidime

6 g (8)

200 mg/kg (8)

Ciprofloxacin

800-1200 mg (8-12)

30 mg/kg (8-12)

Meropenem

6 g (8)

120 mg/kg (8)

Master list of dosages by antimicrobial agent for adult and pediatric bacterial meningitis

Table 15. Master list of dosages by antimicrobial agent for adult and pediatric bacterial meningitis. (Open Table in a new window)

Antimicrobial Agent

Adults: Total Daily Dose (Dose Interval in Hours)

Pediatrics: Total Daily Dose (Dose Interval in Hours)

Amikacin

15 mg/kg (8)

22.5 mg/kg (8)

Ampicillin

12 g (4)

300-400 mg/kg (6)

Aztreonam

6-8 g (6-8)

120 mg/kg (6-8)

Cefepime

6 g (8)

150 mg/kg (8)

Cefotaxime

8-12 g (4-6)

300 mg/kg (6-8)

Ceftazidime

6 g (8)

200 mg/kg (8)

Ceftriaxone

4 g (12)

100 mg/kg (12-24)

Ciprofloxacin

800-1200 mg (8-12)

30 mg/kg (8-12)

Gentamicin

5 mg/kg (8)

7.5 mg/kg (8)

Meropenem

6 g (8)

120 mg/kg (8)

Moxifloxacin

400 mg (24)

Dose not established

Nafcillin

12 g (4)

200 mg/kg (6)

Penicillin G potassium

24 million units (4)

300,000 units/kg (4-6)

Rifampin

600 mg (24)

20 mg/kg (24)

Tobramycin

5 mg/kg (8)

7.5 mg/kg (8)

Trimethoprim-sulfamethoxazole (cotrimoxazole)

10-20 mg/kg (6-12)

10-20 mg/kg (6-12)

Vancomycin

30-60 mg/kg (8-12)

60 mg/kg (6)