Empiric Antibiotic Therapy for Nosocomial Meningitis
For nosocomial meningitis, empiric therapy should include vancomycin plus an anti-pseudomonal beta-lactam such as cefepime, ceftazidime, or meropenem to ensure adequate coverage of resistant gram-positive and gram-negative organisms. 1, 2
Recommended Empiric Regimen
- Vancomycin 15-20 mg/kg IV every 8-12 hours (target serum trough concentrations of 15-20 mg/mL) 3, 1 PLUS ONE OF:
- Cefepime 2g IV every 8 hours 1
- Ceftazidime 2g IV every 8 hours 1, 4
- Meropenem 2g IV every 8 hours 5, 4
Rationale for Empiric Coverage
Nosocomial meningitis commonly involves resistant pathogens including:
Penicillin monotherapy is inappropriate for nosocomial meningitis due to high rates of resistant organisms 3
Inadequate empiric coverage is associated with increased mortality - in one study, 37% of patients with Acinetobacter meningitis received inappropriate initial therapy 4
Special Considerations
External Ventricular Drain (EVD) Related Infections
- EVD-related infections account for 85.7% of nosocomial meningitis cases 4
- Early removal of EVD is critical for improved outcomes 4
- Persistent EVD state is independently associated with poor prognosis (p=0.021) 4
Carbapenem-Resistant Gram-Negative Infections
For carbapenem-resistant gram-negative organisms, consider adding intrathecal therapy: 2
Clinical and microbiological success has been reported in 53% of cases with intrathecal therapy for carbapenem-resistant infections 2
Duration of Therapy
- For uncomplicated cases: 10-14 days of therapy 1
- For complicated cases or resistant organisms: 21 days or longer 1
- Continue therapy until CSF cultures are negative and clinical improvement is observed 1, 4
Adjustments Based on Culture Results
- Once the causative organism is identified, narrow therapy based on susceptibility testing 1
- For Staphylococcus aureus: Flucloxacillin (for MSSA) or continue vancomycin (for MRSA); consider adding rifampin 3
- For Pseudomonas aeruginosa: Combination therapy is recommended (carbapenem plus aminoglycoside or fluoroquinolone) 3
- For Acinetobacter species: Based on susceptibility, use meropenem or consider intrathecal therapy if carbapenem-resistant 2, 4
Common Pitfalls to Avoid
- Delaying antibiotic administration - therapy should be initiated immediately upon suspicion of nosocomial meningitis 1
- Using penicillin alone for nosocomial meningitis (inadequate coverage) 3
- Using single-agent therapy for Pseudomonas infections 3
- Failing to remove infected EVDs or shunts 4
- Inadequate dosing that doesn't achieve sufficient CSF penetration 1
- Underestimating the prevalence of carbapenem-resistant organisms in hospital settings 2, 4
Monitoring Response
- Monitor clinical response (fever, neurological status) 1
- Follow CSF parameters (cell count, glucose, protein) 2
- Consider repeat CSF cultures to document sterilization in treatment-resistant cases 1
- Monitor for drug toxicity, especially with vancomycin (nephrotoxicity) and aminoglycosides 1
Remember that nosocomial meningitis carries a high mortality rate (16.5-32%) and requires aggressive management with appropriate broad-spectrum antibiotics and source control when applicable 2, 4.