What antibiotics are recommended for a dog bite?

Antibiotic Recommendations for Dog Bite Wounds

Amoxicillin-clavulanate is the first-line antibiotic therapy recommended for dog bite wounds as it provides coverage against both aerobic and anaerobic bacteria commonly found in these wounds. 1, 2

First-Line Treatment

• Amoxicillin-clavulanate (oral) at a dose of 875/125 mg twice daily for adults is the recommended first-line therapy 1
• For pediatric patients, the recommended dose is 45 mg/kg/day divided every 12 hours 2
• Treatment duration should be 3-5 days for preemptive therapy in high-risk wounds 1, 2

Alternative Options for Penicillin-Allergic Patients

• For non-anaphylactic penicillin allergy: Doxycycline 100 mg twice daily (not recommended for children under 8 years) 1, 2
• For severe penicillin allergy: Consider fluoroquinolones plus metronidazole for adequate anaerobic coverage 1, 2
• Intravenous options include:
  • Ampicillin-sulbactam (1.5-3.0 g every 6-8 hours) 1
  • Piperacillin-tazobactam (3.37 g every 6-8 hours) 1
  • Carbapenems (ertapenem, imipenem, meropenem) 1

Microbiology of Dog Bite Wounds

• Dog bite wounds typically contain multiple organisms (average of 5 different bacterial types) 1
• Common pathogens include:
  • Pasteurella species (found in approximately 50% of dog bite wounds) 1
  • Staphylococcus aureus and Streptococcus species (found in approximately 40% of bites) 1
  • Anaerobes including Bacteroides, Fusobacterium, Porphyromonas, and Prevotella species 1
  • Capnocytophaga canimorsus (particularly concerning in immunocompromised patients) 1

Indications for Preemptive Antibiotic Therapy

Preemptive antibiotic therapy for 3-5 days is strongly recommended for patients with dog bites who:

• Are immunocompromised 1
• Are asplenic 1
• Have advanced liver disease 1
• Have preexisting or resultant edema of the affected area 1
• Have moderate to severe injuries, especially to the hand or face 1, 3
• Have injuries that may have penetrated the periosteum or joint capsule 1
• Present >9 hours after injury 1

Additional Management Considerations

• Wounds should be thoroughly cleaned and irrigated with sterile normal saline 1, 3
• Tetanus prophylaxis should be administered if not vaccinated within the past 10 years 2, 3
• Consultation with local health officials regarding rabies post-exposure prophylaxis is recommended 1, 2

Common Pitfalls to Avoid

• Avoid first-generation cephalosporins (e.g., cephalexin), penicillinase-resistant penicillins (e.g., dicloxacillin), macrolides (e.g., erythromycin), and clindamycin alone as they have poor activity against Pasteurella multocida 1
• Do not delay treatment for high-risk wounds as infections can progress rapidly, particularly with hand wounds 1, 3
• Do not close puncture wounds or wounds with high risk of infection, except for facial wounds where cosmetic concerns are paramount 2, 3

Amoxicillin-clavulanate has been shown to be effective in multiple studies and is consistently recommended across guidelines due to its broad spectrum of activity against the polymicrobial nature of dog bite wounds 1, 2, 3.