Treatment of Infected Cat Bite Wounds
For an infected cat bite wound, start amoxicillin-clavulanate 875/125 mg orally twice daily for 7-10 days, combined with thorough wound irrigation and elevation of the affected area. 1, 2
Immediate Wound Management
- Irrigate the wound thoroughly with sterile normal saline to remove debris and bacterial contamination—avoid povidone-iodine or antibiotic solutions as they offer no additional benefit 1
- Do not close infected wounds—they must heal by secondary intention or delayed primary closure 1
- Remove superficial debris cautiously; avoid aggressive debridement that enlarges the wound 1
- Elevate the affected body part for the first few days, especially if swollen, as this accelerates healing 1
Antibiotic Selection Algorithm
First-Line Oral Therapy (Outpatient)
Amoxicillin-clavulanate is the preferred agent because it provides comprehensive coverage against the polymicrobial flora in cat bites, including Pasteurella multocida (present in 75% of cat bite wounds), anaerobes (65% of cases), staphylococci, and streptococci 1, 2
Alternative Oral Options (if penicillin allergy)
- Doxycycline as monotherapy—has excellent activity against P. multocida 1, 2
- Moxifloxacin as monotherapy 2
- Clindamycin plus a fluoroquinolone (ciprofloxacin or levofloxacin) 1, 2
- Other fluoroquinolones or cefuroxime must be combined with metronidazole or clindamycin for anaerobic coverage 1
Intravenous Therapy (Severe Infections, Hospitalization Required)
Consider IV therapy if the patient has systemic symptoms (fever, chills), rapidly progressing infection, or failed outpatient treatment 2:
- Ampicillin-sulbactam 1, 2
- Piperacillin-tazobactam 1, 2
- Cefoxitin (second-generation cephalosporin) 1, 2
- Carbapenems (ertapenem, imipenem, meropenem) 1, 2
- Ceftriaxone plus metronidazole 2
Critical Antibiotics to AVOID
Never use these agents alone as they have poor activity against P. multocida, which is present in 75% of cat bites 1:
- First-generation cephalosporins (cephalexin)
- Penicillinase-resistant penicillins (dicloxacillin)
- Macrolides (erythromycin, azithromycin)
- Clindamycin monotherapy
Treatment Duration Based on Infection Severity
- Uncomplicated soft tissue infection: 7-10 days 2
- Septic arthritis: 3-4 weeks 1, 2
- Osteomyelitis: 4-6 weeks 1, 2
- Tendonitis: 3-4 weeks 1
High-Risk Features Requiring Aggressive Management
Hand wounds are particularly serious and often require longer treatment courses due to higher rates of complications 1, 2. Watch for:
- Pain disproportionate to injury near a bone or joint—suggests periosteal penetration or septic arthritis 1
- Signs of deep structure involvement (tendon, joint capsule, bone) 1, 2
- Rapid progression despite initial therapy 1
Special Patient Populations at Higher Risk
Consider hospitalization and IV therapy for patients with 1, 2:
- Asplenia or advanced liver disease—at risk for Capnocytophaga canimorsus bacteremia and fatal sepsis
- Immunocompromised status
- Pre-existing edema of the affected area
- Prosthetic joints or heart valves
Essential Adjunctive Measures
- Update tetanus prophylaxis if not current within 10 years (0.5 mL intramuscularly) 1, 2
- Assess rabies risk and consult local health department for postexposure prophylaxis recommendations 1, 2
- Follow-up within 24 hours by phone or office visit to assess response to therapy 1
- Hospitalize if infection progresses despite appropriate outpatient management 1
Common Pitfalls
Cat bites are more severe than dog bites despite appearing less traumatic—they have deeper puncture wounds with higher rates of osteomyelitis (due to penetration of periosteum) and septic arthritis 1. The microbiology is also more challenging, with 65% containing anaerobes and 75% containing Pasteurella species 1. Never underestimate a cat bite to the hand, as these carry the greatest infection risk 3.
If a patient develops severe diarrhea or bloody stools during or after antibiotic therapy, consider Clostridioides difficile infection and contact a physician immediately 4, 5.