What is the recommended antibiotic treatment for a dog bite?

Recommended Antibiotic Treatment for Dog Bite Wounds

Amoxicillin-clavulanate is the first-line antibiotic treatment for dog bite wounds due to its effectiveness against both aerobic and anaerobic bacteria commonly found in these infections. 1

Microbiology of Dog Bite Wounds

Dog bite wounds typically contain a complex mixture of bacteria:

• Pasteurella species (found in 50% of dog bites) 1
• Staphylococci and streptococci (found in ~40% of bites) 1
• Capnocytophaga canimorsus (particularly dangerous in asplenic or liver disease patients) 1
• Anaerobes including Bacteroides, Fusobacterium, Porphyromonas, and Prevotella species 1
• Average of 5 different bacterial species per wound 1

Antibiotic Recommendations

First-line oral therapy:

• Amoxicillin-clavulanate 875/125 mg twice daily 1

Alternative oral options (if penicillin allergic):

• Doxycycline 100 mg twice daily (excellent activity against Pasteurella) 1
• Fluoroquinolones (ciprofloxacin, levofloxacin, moxifloxacin) plus metronidazole for anaerobic coverage 1

Intravenous options (for severe infections):

• Ampicillin-sulbactam 1.5-3.0 g every 6-8 hours 1
• Piperacillin-tazobactam 3.37 g every 6-8 hours 1
• Second-generation cephalosporins (e.g., cefoxitin) 1
• Carbapenems (ertapenem, imipenem, meropenem) 1

Antibiotics to Avoid

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

Treatment Algorithm

1. Assess wound severity and infection risk:

   • High-risk features: puncture wounds, hand/face/foot location, immunocompromised host, moderate-severe injury, delayed presentation (>8 hours), or periosteum/joint capsule involvement 1, 2

2. For low-risk wounds with no signs of infection:

   • Consider observation without antibiotics if wound is superficial, not on hand/face, and patient is immunocompetent 1

3. For high-risk wounds or established infections:

   • Start amoxicillin-clavulanate 875/125 mg twice daily for 3-5 days 1, 3
   • For severe infections requiring hospitalization, use IV antibiotics listed above

4. Duration of therapy:

   • Uncomplicated wounds: 3-5 days 1
   • Complicated infections (osteomyelitis, septic arthritis): 4-6 weeks for osteomyelitis, 3-4 weeks for synovitis 1

Important Considerations

• Proper wound care is essential: cleanse with normal saline, remove debris, consider debridement if needed 1, 3
• Evaluate need for tetanus prophylaxis (administer if >10 years since last dose) 1
• Consider rabies post-exposure prophylaxis; consult local health officials 1
• Monitor closely for signs of worsening infection, especially with hand wounds which have higher complication rates 1

Common Pitfalls to Avoid

• Using antibiotics with poor activity against Pasteurella (e.g., first-generation cephalosporins, dicloxacillin)
• Failing to consider rabies prophylaxis, especially with unfamiliar or unvaccinated animals
• Inadequate wound irrigation and debridement, which are critical for preventing infection
• Delayed treatment of high-risk wounds (e.g., hand wounds, puncture wounds), which can lead to serious complications including osteomyelitis and septic arthritis

Remember that while antibiotics are important, proper wound care including thorough irrigation and debridement is equally crucial in preventing infection complications from dog bites.