What is the recommended antibiotic for a dog bite?

Antibiotic Treatment for Dog Bites

Amoxicillin-clavulanate 875/125 mg twice daily is the recommended first-line antibiotic for dog bite infections due to its excellent coverage against Pasteurella multocida and other common pathogens found in dog bites. 1

Microbiology of Dog Bite Wounds

Dog bite wounds typically contain a polymicrobial mix of bacteria including:

• Pasteurella multocida (common in 75% of animal bites)
• Staphylococci and streptococci (found in ~40% of bites)
• Anaerobic bacteria
• Other organisms including Capnocytophaga canimorsus, Fusobacterium, Bacteroides, and Porphyromonas species 1, 2

First-Line Treatment

• Amoxicillin-clavulanate 875/125 mg twice daily for 5-7 days is the treatment of choice 1
• This combination provides excellent coverage against the polymicrobial nature of dog bite infections
• Duration may be extended if no improvement is seen after 5 days 1

Alternative Options for Penicillin-Allergic Patients

For patients with penicillin allergies, the following alternatives are recommended:

• Doxycycline (excellent alternative) 1
• Clindamycin plus a fluoroquinolone 1
• Metronidazole plus a fluoroquinolone 1
• Trimethoprim-sulfamethoxazole plus metronidazole 1

Antibiotics to Avoid

The following antibiotics should be avoided due to poor activity against P. multocida:

• First-generation cephalosporins
• Penicillinase-resistant penicillins
• Macrolides
• Clindamycin alone 1

Wound Management

Proper wound care is crucial alongside antibiotic therapy:

1. Cleanse thoroughly with sterile normal saline
2. Remove superficial debris
3. Elevate the affected area
4. Do not close infected wounds 1

Special Considerations

High-Risk Wounds Requiring Prophylactic Antibiotics

• Dog bites to the hand
• Deep puncture wounds
• Wounds requiring surgical debridement
• Wounds involving joints, tendons, or bones
• Immunocompromised patients 1

Indications for Hospitalization

• Severe infections with systemic symptoms
• Deep infections involving tendons or joints
• Hand infections
• Immunocompromised patients with moderate to severe infections 1

Additional Preventive Measures

• Tetanus toxoid (0.5 mL intramuscularly) should be administered if vaccination status is outdated or unknown 1
• Consider rabies prophylaxis for feral and wild animal bites (consult local department of health) 1

Follow-Up

• Assess for response to treatment within 24-48 hours
• Monitor for signs of worsening infection (increasing pain, erythema, swelling, or purulent drainage)
• Consider inflammatory markers and wound culture to guide antibiotic therapy if infection worsens 1

Common Pitfalls

• Failing to recognize the polymicrobial nature of dog bite infections
• Using antibiotics with poor coverage against Pasteurella multocida
• Inadequate wound cleaning and debridement
• Delayed treatment, especially for high-risk bites
• Premature wound closure of potentially infected bites