Antibiotic Treatment for Dog Bites
Amoxicillin-clavulanate is the first-line antibiotic for dog bite wounds, providing optimal coverage against the polymicrobial flora including Pasteurella species, staphylococci, streptococci, and anaerobes. 1, 2
First-Line Treatment
- Amoxicillin-clavulanate is the oral antibiotic of choice for empiric treatment of dog bites, recommended by the American College of Emergency Physicians and multiple infectious disease guidelines 1, 2
- This combination effectively addresses beta-lactamase-producing organisms commonly present in animal bite wounds 1
- Treatment duration should be 7-14 days depending on infection severity 2
Microbiological Rationale
- Dog bite wounds are polymicrobial, containing an average of 5 different bacterial species per wound 1
- Pasteurella species are isolated in approximately 50% of dog bites and require specific antibiotic coverage 1, 2
- Staphylococci and streptococci are present in roughly 40% of cases 1, 2
- Capnocytophaga canimorsus can cause fatal bacteremia and sepsis, particularly in asplenic or immunocompromised patients 1
Alternative Options for Penicillin Allergy
- Doxycycline 100 mg twice daily is the preferred alternative for penicillin-allergic patients, with excellent activity against Pasteurella multocida 1, 2
- Fluoroquinolones (ciprofloxacin, levofloxacin) plus metronidazole for anaerobic coverage 1, 2
- Moxifloxacin 400 mg daily can be used as monotherapy, covering both aerobic and anaerobic organisms 1, 3
Intravenous Options for Severe Infections
- Ampicillin-sulbactam or other beta-lactam/beta-lactamase inhibitor combinations 1, 2
- Piperacillin-tazobactam for hospitalized patients 1
- Second-generation cephalosporins such as cefoxitin 1, 2
- Carbapenems (ertapenem, imipenem, meropenem) for complicated infections 1
Critical Antibiotics to AVOID
These antibiotics have inadequate coverage and can lead to treatment failure:
- First-generation cephalosporins (cefalexin/cephalexin) - insufficient Pasteurella coverage 1, 2
- Penicillinase-resistant penicillins (dicloxacillin) - poor activity against bite wound flora 1
- Macrolides (erythromycin) as monotherapy 1
- Clindamycin alone - inadequate coverage 1
Indications for Prophylactic Antibiotics
Prophylactic antibiotics are indicated for:
- Puncture wounds, especially those penetrating bone, tendon sheath, or joints 4
- Wounds requiring primary closure 4
- Hand, foot, face, or genital area bites 1, 4
- Moderate to severe bite wounds 4
- Immunocompromised or asplenic patients (who are at highest risk for Capnocytophaga sepsis) 5, 4
Essential Wound Management
- Copious irrigation and thorough debridement are as important as antibiotics for infection prevention 1, 3
- Most infected wounds should NOT be closed primarily 1
- Facial wounds may be an exception and can be closed primarily with meticulous wound care, copious irrigation, and prophylactic antibiotics 1, 3
- Update tetanus prophylaxis if not current within the last 10 years 1, 4
High-Risk Complications to Monitor
- Hand wounds are often more severe than wounds to fleshy body parts 1
- Pain disproportionate to injury severity near bone or joint suggests periosteal penetration and requires aggressive evaluation 1
- Serious complications include septic arthritis, osteomyelitis, subcutaneous abscess formation, tendinitis, and bacteremia 1
- These complications require prolonged therapy (4-6 weeks for osteomyelitis) 1