What is the recommended treatment for cat bite prophylaxis?

Cat Bite Prophylaxis

Recommended Antibiotic Regimen

Amoxicillin-clavulanate 875/125 mg twice daily is the first-line prophylactic antibiotic for cat bites. 1, 2

This recommendation is based on the unique microbiology of cat bite wounds:

• Pasteurella multocida is present in 75% of cat bites and requires specific coverage 2
• Cat bites yield an average of 5 different bacterial isolates, with approximately 60% containing mixed aerobic and anaerobic bacteria 2
• Staphylococci and streptococci are found in ~40% of bites 2
• Anaerobic bacteria are present in 65% of cat bites 2

Amoxicillin-clavulanate provides excellent coverage against P. multocida, good activity against staphylococci and streptococci, and effective coverage against anaerobic organisms. 1, 2

Indications for Prophylactic Antibiotics

Prophylactic antibiotics should be given early to all cat bite patients regardless of wound appearance, as cat bites have a 30-50% infection rate—significantly higher than dog bites. 2, 3, 4

Specific high-risk scenarios requiring prophylaxis include: 1, 2, 3

• All puncture wounds (which are characteristic of cat bites)
• Hand, foot, face, or wounds near joints
• Immunocompromised patients
• Wounds with deep tissue involvement
• Presentation >8-12 hours after injury

Alternative Regimens for Penicillin Allergy

For patients with penicillin allergies: 1, 2, 3

• Doxycycline 100 mg twice daily (excellent activity against P. multocida; some streptococci may be resistant) 1, 2
• Moxifloxacin 400 mg daily (monotherapy with good anaerobic coverage) 1
• Ciprofloxacin 500-750 mg twice daily PLUS metronidazole 250-500 mg three times daily (ciprofloxacin alone misses anaerobes) 1, 2

Critical Pitfalls to Avoid

Never use first-generation cephalosporins, penicillinase-resistant penicillins (like dicloxacillin alone), macrolides (including azithromycin), or clindamycin monotherapy for cat bites. 1, 2

These agents have poor or insufficient activity against P. multocida, and clinical failures have been documented with macrolides. 2 While azithromycin is appropriate for cat scratch disease caused by Bartonella henselae, it is NOT appropriate for cat bite wound prophylaxis or treatment. 2, 3

Essential Wound Management

Beyond antibiotics, proper wound care is critical: 1, 5, 6

• Thoroughly cleanse with sterile normal saline (no need for iodine or antibiotic solutions) 1
• Copiously irrigate using a 20-mL or larger syringe 5, 6
• Remove superficial debris; avoid deep debridement unless significant devitalized tissue present 1, 3
• Do NOT primarily close infected wounds or most cat bite puncture wounds 1
• Elevate the affected extremity to reduce swelling 2

Hand Wounds Require Special Attention

Cat bites on the hand have the highest risk of infection and serious complications, including septic arthritis, osteomyelitis, and tenosynovitis. 2, 7, 8 Even small external wounds can harbor deep infection. 4 These patients require:

• Early prophylactic antibiotics 4
• Close observation with follow-up within 24 hours 1
• Low threshold for imaging if bone or joint involvement suspected 2
• Consideration for single initial parenteral antibiotic dose before starting oral therapy 1

Tetanus and Rabies Considerations

Administer tetanus toxoid if not vaccinated within 10 years; Tdap is preferred over Td if not previously given. 1

Rabies prophylaxis should be considered for all feral and wild cat bites. 1 For domestic cats:

• A healthy cat that bites may be confined and observed for 10 days 1
• If the cat is stray, unwanted, or develops signs of illness, it should be euthanized and tested for rabies 1
• Consult local health department about rabies risk in your geographic area 1

Duration of Prophylaxis

For uncomplicated prophylaxis, typical duration is 3-5 days. 5, 6 However, if infection develops:

• Cellulitis or soft tissue infection: 1-2 weeks (up to 3-4 weeks if extensive or slow to resolve) 2, 3
• Septic arthritis: 3-4 weeks total 1, 2
• Osteomyelitis: 4-6 weeks total 1, 2

When to Use IV Antibiotics

Switch to IV therapy for: 2

• Established infection with systemic signs (fever, lymphangitis, significant cellulitis)
• Deep tissue involvement (septic arthritis, osteomyelitis, tenosynovitis)
• Immunocompromised patients with moderate to severe injuries

First-line IV regimens: 1, 2

• Ampicillin-sulbactam 1.5-3.0 g every 6-8 hours
• Piperacillin-tazobactam 3.37 g every 6-8 hours
• Carbapenems (ertapenem, imipenem, or meropenem) for severe infections

Transition to oral amoxicillin-clavulanate once clinical improvement occurs. 2