Is Augmentin (amoxicillin-clavulanate) effective for treating cat bites?

Treatment of Cat Bites with Augmentin (Amoxicillin-Clavulanate)

Augmentin (amoxicillin-clavulanate) is the recommended first-line treatment for cat bites due to its excellent coverage against Pasteurella multocida and other common pathogens found in cat bite wounds. 1

Microbiology of Cat Bites

• Cat bites have a high infection rate of 30-50%, significantly higher than dog bites (5-25%) 1
• Pasteurella multocida is isolated from 75% of cat bite wounds, making it the predominant pathogen of concern 1
• Cat bites also contain mixed aerobic and anaerobic bacteria (approximately 60% of wounds), including staphylococci and streptococci (found in ~40% of bites) 1
• Cat bites have a greater prevalence of anaerobes (65%) compared to dog bites (50%) 1

Treatment Recommendations

First-Line Therapy

• Oral amoxicillin-clavulanate (Augmentin) 875/125 mg twice daily is the recommended empiric treatment for cat bites 1
• For less severe infections, amoxicillin-clavulanate 500 mg three times daily is also appropriate 1
• The FDA has approved amoxicillin-clavulanate for skin and skin structure infections caused by beta-lactamase-producing isolates of Staphylococcus aureus, Escherichia coli, and Klebsiella species 2

Alternative Options

• Doxycycline 100 mg twice daily (excellent activity against P. multocida, but some streptococci are resistant) 1
• Combination of penicillin 500 mg four times daily plus dicloxacillin 500 mg four times daily 1
• For patients requiring intravenous therapy: ampicillin-sulbactam, piperacillin-tazobactam, or carbapenems 1

Medications to Avoid

• First-generation cephalosporins (e.g., cephalexin)
• Penicillinase-resistant penicillins (e.g., dicloxacillin)
• Macrolides (e.g., erythromycin)
• Clindamycin alone (all have poor activity against P. multocida) 1

Duration of Therapy

• 5-7 days for uncomplicated infections 3, 4
• 10-14 days for complicated infections (e.g., involving joints, bones, or tendon sheaths) 1, 5

Special Considerations

Hand Infections

• Cat bites to the hand carry the highest risk of infection 3
• Wounds over joints or tendon sheaths require careful evaluation and may need surgical exploration 5
• Patients presenting >24 hours after injury with signs of infection (swelling, redness, limited mobility) should be evaluated for complications such as tenosynovitis 5

Complications

• Potential complications include septic arthritis, osteomyelitis, subcutaneous abscess formation, tendonitis, and rarely bacteremia 1
• Pain disproportionate to the injury near a bone or joint should raise suspicion for periosteal penetration 1
• Complications may require prolonged therapy (3-4 weeks for synovitis, 4-6 weeks for osteomyelitis) 1

Wound Management

• Thorough cleansing and irrigation with sterile normal saline is essential 1, 6
• Explore wounds for tendon or bone involvement and possible foreign bodies 6
• Primary closure may be considered for cosmetically important areas (face) or gaping wounds, but many cat bite puncture wounds should be left open 6

Practical Algorithm for Cat Bite Management

1. Clean and irrigate wound thoroughly
2. Assess for high-risk features (hand location, deep puncture, immunocompromised host)
3. Start amoxicillin-clavulanate 875/125 mg twice daily for 5-7 days
4. Consider leaving puncture wounds open to heal by secondary intention
5. Follow up within 24-48 hours to assess for signs of infection
6. If signs of infection develop despite antibiotics, consider imaging and surgical consultation

Augmentin's combination of amoxicillin with the beta-lactamase inhibitor clavulanic acid provides excellent coverage against the polymicrobial nature of cat bite infections, particularly P. multocida which is the most concerning pathogen 2, 3.