What are the recommended antibiotic choices for the treatment of subdural empyema?

Antibiotic Choices for Subdural Empyema

For subdural empyema, empiric antibiotic therapy should include vancomycin (30-60 mg/kg/day IV in divided doses) plus trimethoprim-sulfamethoxazole (TMP-SMX) with rifampin as an additional option, to cover the most common causative organisms including streptococci, staphylococci, and anaerobes. 1

Pathogen Coverage Considerations

When selecting antibiotics for subdural empyema, it's essential to target the most common causative organisms:

• Common pathogens:

  • Streptococci (especially Streptococcus milleri group/anginosus)
  • Staphylococcus aureus
  • Anaerobic bacteria
  • Gram-negative organisms (in hospital-acquired cases) 2

• Origin-based considerations:

  • Sinusitis-related: Primarily streptococci and anaerobes
  • Post-neurosurgical: S. aureus, S. epidermidis, Pseudomonas
  • Otitis-related: Mixed flora including anaerobes
  • Hematogenous spread: Typically streptococci or S. aureus 2, 3

First-Line Antibiotic Regimens

For CNS Infections - Subdural Empyema:

• Initial empiric therapy (adults):

  • Vancomycin 30-60 mg/kg/day IV in divided doses PLUS
  • TMP-SMX (TMP 600 mg PO QD or 300-450 mg PO q12h) PLUS
  • Consider rifampin 5 mg/kg/dose IV q8-12h 1

• Alternative regimen:

  • Linezolid 600 mg IV/PO q12h 1

Duration of Therapy:

• 4-6 weeks of antibiotic therapy is recommended 1

Special Populations

Pediatric Patients:

• Initial empiric therapy:

  • Vancomycin 15 mg/kg/dose IV q6h PLUS
  • Linezolid 10 mg/kg/dose PO/IV q8h (not exceeding 600 mg/dose) 1

• For community-acquired infections in children:

  • Options include:
    • Cefuroxime plus metronidazole
    • Co-amoxiclav
    • Penicillin and flucloxacillin
    • Clindamycin (especially for penicillin-allergic patients) 1

Approach Based on Acquisition Setting

Community-Acquired Infection:

• Cover for streptococci (including S. milleri), S. aureus, and anaerobes
• Consider adding metronidazole if anaerobic coverage is not provided by primary agent 1

Hospital-Acquired Infection:

• Broader spectrum coverage required:
  • Piperacillin-tazobactam
  • Ceftazidime
  • Meropenem (with or without metronidazole) 1

Important Clinical Considerations

• Avoid aminoglycosides as they have poor penetration into CNS and may be inactive in acidic environments 1

• Surgical drainage is mandatory in virtually all cases - antibiotic therapy alone is insufficient 2, 4

• Do not delay antibiotics while awaiting surgical drainage - early antibiotic administration is critical and does not compromise microbiological diagnosis when comprehensive culture techniques are used 4

• Adjust therapy based on culture results once available, but don't delay initial empiric coverage 1

• Monitor for complications including increased intracranial pressure, seizures, and neurological deficits 5

• Address the primary source of infection (e.g., sinusitis, otitis) concurrently for optimal outcomes 4

Antibiotic Considerations for Specific Situations

• When organism is unknown: Cover S. aureus, streptococci (especially S. milleri group), anaerobes, and gram-negative organisms with a combination of:

  1. Nafcillin/oxacillin/vancomycin PLUS
  2. A third-generation cephalosporin PLUS
  3. Metronidazole 2

• For penicillin-allergic patients: Clindamycin can provide adequate coverage for most common pathogens 1

The rapid identification and aggressive treatment of subdural empyema with appropriate antibiotics and surgical drainage is essential to reduce morbidity and mortality in this life-threatening condition.