What are the recommended antibiotics (Abx) for meningitis?

Recommended Antibiotics for Bacterial Meningitis

The first-line empirical treatment for suspected bacterial meningitis is ceftriaxone 2g IV every 12 hours or cefotaxime 2g IV every 6 hours, with additional agents based on patient age, risk factors, and local resistance patterns. 1, 2

Initial Empirical Treatment Algorithm

For Adults <60 Years:

• First choice: Ceftriaxone 2g IV every 12 hours OR Cefotaxime 2g IV every 6 hours 1
• Alternative (if severe beta-lactam allergy): Chloramphenicol 25mg/kg IV every 6 hours 1

For Adults ≥60 Years:

• First choice: Ceftriaxone 2g IV every 12 hours OR Cefotaxime 2g IV every 6 hours PLUS Amoxicillin 2g IV every 4 hours 1
• Alternative (if severe beta-lactam allergy): Chloramphenicol 25mg/kg IV every 6 hours AND Co-trimoxazole 10-20mg/kg (of trimethoprim component) in four divided doses 1

Special Considerations:

• If risk of penicillin-resistant pneumococci (e.g., recent travel to areas with high resistance rates): Add Vancomycin 15-20mg/kg IV every 12 hours OR Rifampicin 600mg IV/oral every 12 hours 1, 2
• If immunocompromised (including diabetics and those with history of alcohol misuse): Add Amoxicillin 2g IV every 4 hours to cover Listeria 1

Pathogen-Specific Treatment

Neisseria meningitidis:

• Continue Ceftriaxone 2g IV every 12 hours OR Cefotaxime 2g IV every 6 hours 1
• Alternative: Benzylpenicillin 2.4g IV every 4 hours 1
• If not treated with ceftriaxone, add single dose of Ciprofloxacin 500mg orally 1
• Duration: 5 days if clinical recovery occurs 1

Streptococcus pneumoniae:

• Penicillin-sensitive (MIC ≤0.06mg/L): Benzylpenicillin 2.4g IV every 4 hours OR continue ceftriaxone/cefotaxime 1
• Penicillin-resistant but cephalosporin-sensitive: Continue ceftriaxone/cefotaxime 1
• Penicillin and cephalosporin-resistant: Ceftriaxone/cefotaxime PLUS Vancomycin 15-20mg/kg IV every 12 hours PLUS Rifampicin 600mg IV/oral every 12 hours 1, 3
• Duration: 10 days if recovered; 14 days if not recovered by day 10 or if resistant strain 1

Haemophilus influenzae:

• Continue Ceftriaxone 2g IV every 12 hours OR Cefotaxime 2g IV every 6 hours 1
• Duration: 10 days 1

Listeria monocytogenes:

• Amoxicillin 2g IV every 4 hours 1
• Alternative: Co-trimoxazole 10-20mg/kg (of trimethoprim component) in 4 divided doses 1
• Duration: 21 days 1

Enterobacteriaceae:

• Continue Ceftriaxone/Cefotaxime and seek specialist advice regarding local resistance patterns 1
• If suspected ESBL-producing organism: Meropenem 2g IV every 8 hours 1, 4
• Duration: 21 days 1

Important Clinical Considerations

Timing of Antibiotics:

• Administer antibiotics immediately after blood cultures are obtained
• Do not delay antibiotics waiting for CSF results if lumbar puncture will be delayed 2

Monitoring and Treatment Adjustment:

• Assess clinical response within 48 hours
• Consider repeat lumbar puncture if no clinical improvement, especially with pneumococcal meningitis with high resistance 1, 2

Common Pitfalls to Avoid:

1. Delaying antibiotic administration - this significantly increases mortality risk
2. Failing to cover Listeria in patients ≥60 years or immunocompromised
3. Not adding vancomycin when risk of penicillin-resistant pneumococci exists
4. Overlooking ciprofloxacin when not using ceftriaxone for meningococcal disease
5. Stopping antibiotics too early - adhere to recommended durations based on pathogen
6. Not adjusting therapy based on culture results and susceptibility patterns

Special Populations:

• Pediatric patients: Ceftriaxone (100mg/kg/day) or Cefotaxime (300mg/kg/day) are preferred for children >3 months 5, 6
• Neonates and infants <3 months: Ampicillin plus Cefotaxime (not Ceftriaxone due to bilirubin displacement concerns) 5

The rapid bactericidal activity of third-generation cephalosporins makes them particularly valuable in meningitis treatment, where quick elimination of pathogens is crucial for reducing mortality and neurological sequelae 7, 8.