What is the recommended treatment for Pasteurella infections?

Treatment of Pasteurella Infections

Penicillin or amoxicillin is the first-line treatment for Pasteurella infections, with doxycycline being an excellent alternative for penicillin-allergic patients. 1, 2

First-Line Treatment Options

Penicillin-Based Therapy

• Penicillin V: 500 mg orally four times daily for 7-10 days 1
• Amoxicillin: 500 mg orally three times daily for 7-10 days 1
• Amoxicillin-clavulanate: 875/125 mg orally twice daily 1
  • Particularly useful for polymicrobial infections (common in animal bites)

For Penicillin-Allergic Patients

• Doxycycline: 100 mg orally twice daily 1, 3
  • Excellent activity against Pasteurella multocida
  • FDA-approved for Pasteurella infections 3
• Fluoroquinolones:
  • Ciprofloxacin: 500-750 mg orally twice daily 1
  • Levofloxacin: 750 mg orally daily 1
  • Moxifloxacin: 400 mg orally daily (good monotherapy option as it covers anaerobes) 1

Treatment Based on Infection Severity

Localized Infections

• Oral antibiotics as listed above for 7-10 days
• Wound care: Thorough cleaning and irrigation with normal saline 1

Severe/Systemic Infections

For patients with systemic signs of infection, immunocompromise, or severe infections:

• Intravenous options:
  • Ampicillin-sulbactam: 1.5-3.0 g IV every 6 hours 1
  • Piperacillin-tazobactam: 3.37 g IV every 6-8 hours 1
  • Carbapenems (imipenem, meropenem, ertapenem) 1
  • Ceftriaxone: 1 g IV every 12-24 hours 1
  • Cefotaxime: 1-2 g IV every 6-8 hours 1

Special Considerations

Animal Bite-Associated Pasteurella Infections

• Pasteurella multocida is the most common pathogen in cat bites (30-50%) and dog bites (5-25%) 1
• Early antibiotic therapy (within 24 hours of bite) is crucial for prevention of infection 1
• Consider tetanus prophylaxis if vaccination not current within 10 years 1
• Preemptive antibiotic therapy (3-5 days) recommended for:
  • Immunocompromised patients
  • Asplenic patients
  • Those with advanced liver disease
  • Moderate to severe injuries, especially to hands or face 1

Pasteurella with Complications

• For osteomyelitis or joint infections: Extended antibiotic course (4-6 weeks) with surgical debridement as needed 4
• For respiratory infections: Consider broader coverage initially until culture results available 1

Monitoring and Follow-up

• Re-evaluate within 48-72 hours to ensure appropriate response to therapy
• Consider changing antibiotics if no improvement after 48 hours
• Longer courses may be needed for deep tissue infections or osteomyelitis 4

Antibiotic Resistance Considerations

• While most Pasteurella strains remain susceptible to penicillins, beta-lactamase production has been reported in some isolates 5
• For suspected resistant strains, amoxicillin-clavulanate, third-generation cephalosporins, or fluoroquinolones are appropriate 5
• Avoid macrolides, first-generation cephalosporins, and clindamycin as they have poor activity against Pasteurella 1, 5

Prevention

• Proper wound care immediately after animal bites or scratches
• Thorough cleaning with soap and water
• Prompt medical attention for all animal bites, especially cat bites which have higher risk of Pasteurella infection 4

Remember that the acute onset of cellulitis, lymphangitis, and serosanguineous or purulent drainage from hand wounds 12-24 hours after cat or dog bites strongly suggests Pasteurella multocida infection and requires immediate treatment 4.