Is azithromycin (Azithromycin) preferred over Augmentin (Amoxicillin/Clavulanate) for treating cat bites?

Treatment of Cat Bites: Amoxicillin-Clavulanate vs. Azithromycin

Amoxicillin-clavulanate (Augmentin) is strongly preferred over azithromycin for treating cat bites due to its superior coverage against Pasteurella multocida, which is present in 75% of cat bite wounds. 1

Microbiology of Cat Bites

• Cat bites have a high infection rate of 20-80% compared to only 3-18% for dog bites 2, 3
• The predominant pathogens in cat bite wounds include:
  • Pasteurella multocida (found in 75% of cat bites) 1
  • Staphylococci and streptococci (found in ~40% of bites) 1
  • Anaerobic bacteria (present in 65% of cat bites) 1
• The average cat bite wound yields 5 different bacterial isolates, with ~60% having mixed aerobic and anaerobic bacteria 1

First-Line Treatment Recommendation

• Amoxicillin-clavulanate (875/125 mg twice daily) is the recommended first-line oral therapy for cat bites 1
• This recommendation is based on:
  • Excellent coverage against P. multocida (100% susceptibility) 2
  • Good activity against staphylococci and streptococci 1
  • Effective coverage against anaerobic organisms 1
  • Clinical evidence supporting its use in bite wounds 3, 4

Why Azithromycin is NOT Preferred

• Azithromycin is specifically recommended for cat scratch disease (caused by Bartonella henselae), not for cat bite infections 1
• While azithromycin shows good activity against P. multocida (94.02% susceptibility) 2, it has several limitations:
  • Insufficient coverage against many anaerobes commonly found in cat bites 1
  • Clinical failures have been documented with macrolides (erythromycin) in treating P. multocida infections 5
  • No specific recommendations for its use in cat bite wounds in major guidelines 1

Alternative Treatment Options

• For patients with penicillin allergies, consider:
  • Doxycycline (100 mg twice daily) - excellent activity against P. multocida 1
  • Fluoroquinolones (e.g., ciprofloxacin 500-750 mg twice daily) - good activity against P. multocida but misses MRSA and some anaerobes 1
  • Second-generation cephalosporins (e.g., cefuroxime 500 mg twice daily) - good activity against P. multocida but misses anaerobes 1

Important Clinical Considerations

• Cat bites on the hand have the highest risk of infection and complications 1, 3
• Prophylactic antibiotics are recommended for cat bites due to the high infection rate 4
• First-generation cephalosporins, penicillinase-resistant penicillins (e.g., dicloxacillin), macrolides (e.g., erythromycin), and clindamycin all have poor activity against P. multocida and should be avoided 1
• Wound care including thorough irrigation and debridement is essential in addition to antibiotic therapy 1
• Consider tetanus prophylaxis and rabies risk assessment as part of bite wound management 3

Potential Complications

• Infectious complications of cat bite wounds include:
  • Septic arthritis and osteomyelitis (especially with hand wounds) 1
  • Subcutaneous abscess formation 1
  • Tendonitis 1
  • Bacteremia (rarely) 1, 5
  • Meningitis (rare but serious) 5

In conclusion, while azithromycin is effective for cat scratch disease, amoxicillin-clavulanate remains the treatment of choice for cat bite wounds due to its superior coverage against the polymicrobial nature of these infections, particularly P. multocida.