What is the recommended treatment for meningitis caused by Streptococcus pneumoniae?

Treatment of Meningitis Caused by Streptococcus pneumoniae

For meningitis caused by Streptococcus pneumoniae, the recommended treatment depends on the antibiotic susceptibility pattern, with a third-generation cephalosporin plus vancomycin being the standard empiric therapy until susceptibility results are available.

Initial Empiric Treatment

Based on Pneumococcal Susceptibility Patterns:

1. For penicillin-susceptible S. pneumoniae (MIC <0.1 mg/mL):

   • Penicillin G or ampicillin 1
   • Alternative: Third-generation cephalosporin (ceftriaxone or cefotaxime) 1

2. For penicillin-intermediate S. pneumoniae (MIC 0.1-1.0 mg/mL):

   • Third-generation cephalosporin (ceftriaxone 2g IV every 12 hours or cefotaxime) 1, 2
   • Alternative: Cefepime or meropenem 1

3. For penicillin-resistant S. pneumoniae (MIC ≥2.0 mg/mL) or cephalosporin-resistant strains (MIC ≥1.0 mg/mL):

   • Vancomycin plus a third-generation cephalosporin 1
   • Alternative: Fluoroquinolone with good CNS penetration 1

Adjunctive Therapy

• Dexamethasone: 10 mg IV every 6 hours should be started with or before the first dose of antibiotics and continued for 4 days in confirmed cases 2
• Rifampicin: Consider adding rifampicin 600 mg twice daily if the organism is highly resistant to cephalosporins, especially if there is a delay in clinical response 1

Treatment Duration

• 10-14 days for pneumococcal meningitis 1, 2
• Consider extending to 14 days for resistant strains or if recovery is delayed 2

Special Considerations

Antibiotic Selection Based on Resistance:

• Vancomycin should never be used alone due to concerns about CSF penetration, especially when dexamethasone is given 2
• In areas with high rates of pneumococcal resistance, empiric therapy should include vancomycin plus a third-generation cephalosporin until susceptibility results are available 1
• The combination of vancomycin and ceftriaxone has shown synergistic activity against resistant pneumococcal strains 3

Alternative Agents:

• Meropenem: Effective for treatment of bacterial meningitis caused by penicillin-susceptible S. pneumoniae at a dose of 40 mg/kg every 8 hours (pediatric) or 2g every 8 hours (adult) 4
• Linezolid: Can be considered as an alternative to vancomycin or rifampicin in combination regimens with a third-generation cephalosporin 5

Monitoring and Response Assessment

• CSF should be sterilized within 24-48 hours of appropriate therapy 6
• Clinical improvement should be evident within 48-72 hours
• Consider repeat lumbar puncture if no clinical improvement after 48 hours, especially with resistant strains
• Monitor for potential long-term sequelae, particularly hearing loss 2

Common Pitfalls to Avoid

1. Delayed initiation of antibiotics: Treatment should begin immediately after obtaining CSF samples
2. Inadequate coverage for resistant strains: Always consider local resistance patterns when selecting empiric therapy
3. Monotherapy for resistant strains: Combination therapy is essential for highly resistant pneumococcal strains
4. Failure to adjust therapy based on susceptibility results: Optimize treatment once culture and sensitivity results are available
5. Inadequate duration of therapy: Complete the full course of antibiotics even if clinical improvement occurs rapidly

Remember that treatment decisions should be guided by local resistance patterns and adjusted based on culture and susceptibility results as soon as they become available.