Cat Bite Infection Treatment
Amoxicillin-clavulanate 875/125 mg twice daily for 7-10 days is the definitive first-line treatment for cat bite infections, providing essential coverage against the polymicrobial flora including Pasteurella multocida, which is present in approximately 75% of cat bite wounds. 1, 2, 3
Why Amoxicillin-Clavulanate is the Gold Standard
- Cat bites have an exceptionally high infection rate of 30-50%, significantly exceeding dog bites (5-25%), making aggressive antibiotic therapy essential 2
- The average cat bite wound contains 5 different bacterial species, with approximately 60% having mixed aerobic and anaerobic bacteria 3, 4
- Pasteurella multocida is isolated in over 50-75% of infected cat bite wounds and demonstrates 100% susceptibility to amoxicillin-clavulanate 2, 5, 6
- Amoxicillin-clavulanate provides comprehensive coverage against the polymicrobial flora including staphylococci, streptococci, and anaerobic organisms that comprise cat bite infections 1, 3
Alternative Oral Regimens (For Penicillin Allergy)
- Doxycycline 100 mg twice daily has excellent activity against P. multocida, though some streptococci may be resistant 1, 2, 3
- Moxifloxacin 400 mg daily provides monotherapy coverage including anaerobes 1
- Combination therapy: Trimethoprim-sulfamethoxazole (for aerobes) PLUS metronidazole (for anaerobes) can be used as an alternative 2
- Ciprofloxacin 500-750 mg twice daily or levofloxacin 750 mg daily have good P. multocida activity but miss MRSA and some anaerobes 1, 3
Intravenous Therapy for Severe Infections
When systemic signs are present (fever, lymphangitis, significant cellulitis, rapidly spreading infection):
- Ampicillin-sulbactam 1.5-3.0 g every 6-8 hours IV is first-line for hospitalized patients 1, 3
- Piperacillin-tazobactam 3.37 g every 6-8 hours IV is an alternative for severe infections 1, 3
- Carbapenems (imipenem-cilastatin 1 g every 6-8 hours IV, meropenem 1 g every 8 hours IV, or ertapenem 1 g daily IV) are reserved for complicated cases 1
- Treat for 3-5 days IV, then transition to oral amoxicillin-clavulanate to complete 7-10 days total 3
Essential Wound Management
- Thoroughly cleanse the wound with sterile normal saline and remove any superficial debris 2
- Do NOT close infected wounds as this traps bacteria and increases infection risk 2
- Elevate the injured body part to accelerate healing 2
- Ensure tetanus prophylaxis is current 2
Critical Antibiotics to AVOID
These are common prescribing errors that lead to treatment failure:
- First-generation cephalosporins (cephalexin, cefazolin) miss P. multocida and anaerobes completely 2, 3
- Penicillinase-resistant penicillins (dicloxacillin, nafcillin) have poor P. multocida activity 1, 3
- Clindamycin alone misses P. multocida despite good activity against staphylococci, streptococci, and anaerobes 1, 2
- Do not rely solely on topical antibiotics without systemic coverage 2
High-Risk Situations Requiring Immediate Escalation
- Hand bites have the highest infection risk and complication rate, including tendosynovitis, septic arthritis, and osteomyelitis 3
- Pain disproportionate to the injury near a bone or joint suggests periosteal penetration and requires urgent surgical evaluation 2
- Complications occur in approximately 18% of infected cat bite patients, including abscess formation, tendonitis, bacteremia, and meningitis 3
- Rapidly progressing infection despite appropriate antibiotic therapy requires hospitalization and IV antibiotics 2
- Immunocompromised patients with any signs of infection require aggressive treatment 2
Special Consideration: MRSA Coverage
- If MRSA is suspected (community-acquired MRSA can be shared between pets and owners), add trimethoprim-sulfamethoxazole 1-2 double-strength tablets twice daily to amoxicillin-clavulanate 3, 4
- Alternatively, use clindamycin 300-450 mg three times daily as monotherapy if penicillin-allergic 3, 7