What is the treatment for Pasteurella multocida infections?

Treatment of Pasteurella multocida Infections

For Pasteurella multocida infections, doxycycline (100 mg twice daily) is recommended as first-line therapy due to its excellent activity against the organism, with amoxicillin-clavulanate (875/125 mg twice daily) as an effective alternative. 1

First-Line Treatment Options

Oral Therapy

• Doxycycline: 100 mg twice daily 1

  • Excellent activity against P. multocida
  • FDA-approved for P. multocida infections 2
  • Particularly useful for respiratory infections 3

• Amoxicillin-clavulanate: 875/125 mg twice daily 1

  • Effective against P. multocida and other common co-infecting organisms
  • Good choice for polymicrobial infections (common in animal bites)

• Penicillin/Amoxicillin: 500 mg four times daily (penicillin) or 500 mg three times daily (amoxicillin) 1, 4

  • Traditional first-line therapy
  • Highly effective against P. multocida
  • Limited coverage for other potential pathogens

Intravenous Therapy (for severe infections)

• Ampicillin-sulbactam: 1.5-3.0 g every 6-8 hours 1
• Piperacillin-tazobactam: 3.37 g every 6-8 hours 1
• Carbapenems (imipenem, meropenem, ertapenem) 1

Alternative Options (for penicillin-allergic patients)

• Fluoroquinolones:

  • Ciprofloxacin: 500-750 mg twice daily 1
  • Levofloxacin: 750 mg daily 1
  • Moxifloxacin: 400 mg daily (monotherapy; also covers anaerobes) 1

• Second/Third-generation cephalosporins:

  • Cefuroxime: 500 mg twice daily (oral) or 1 g every 12 hours (IV) 1
  • Ceftriaxone: 1 g every 12 hours (IV) 1
  • Cefotaxime: 1-2 g every 6-8 hours (IV) 1

• Trimethoprim-sulfamethoxazole: 160-800 mg twice daily 1, 5

  • Good activity against aerobes but poor against anaerobes

Treatment Algorithm

1. Assess infection severity:

   • Localized infection: Oral therapy
   • Systemic infection, immunocompromised host, or deep tissue involvement: IV therapy

2. Consider infection source:

   • Animal bite-related: Cover for polymicrobial infection with amoxicillin-clavulanate
   • Respiratory infection: Doxycycline or penicillin
   • Bacteremia: IV therapy with ampicillin-sulbactam or piperacillin-tazobactam

3. Evaluate patient factors:

   • Penicillin allergy: Use doxycycline, fluoroquinolones, or trimethoprim-sulfamethoxazole
   • Renal/hepatic impairment: Adjust dosing accordingly

Duration of Therapy

• Uncomplicated soft tissue infections: 5-7 days
• Respiratory infections: 7-14 days
• Bacteremia: 10-14 days
• Osteomyelitis or septic arthritis: 4-6 weeks 1

Important Clinical Considerations

• P. multocida infections typically develop rapidly after animal exposure (especially cat or dog bites) with marked inflammation within 24 hours 6, 4
• Infections can progress from localized cellulitis to invasive disease including osteomyelitis, septic arthritis, and bacteremia 4
• Hand wounds are particularly concerning and require prompt treatment 4
• Clindamycin should be avoided as it has poor activity against P. multocida 1
• First-generation cephalosporins (cephalexin), macrolides (erythromycin), and penicillinase-resistant penicillins (dicloxacillin) have poor activity against P. multocida 1

Adjunctive Measures

• Thorough wound cleaning and irrigation for bite-related infections
• Surgical debridement may be necessary for abscesses or necrotic tissue
• Tetanus prophylaxis should be considered if vaccination is not current 1
• Wounds should not be closed if infected 1

By following this treatment approach and selecting appropriate antimicrobial therapy based on infection severity and patient factors, P. multocida infections can be effectively managed with excellent outcomes.