Animal Bite Infections: Antibiotic Treatment Guidelines

First-Line Treatment Recommendation

The Infectious Diseases Society of America recommends amoxicillin-clavulanate as the first-line antibiotic for animal bite wounds due to its broad coverage of polymicrobial flora, including Pasteurella species, Staphylococcus aureus, Streptococcus species, and anaerobic bacteria, with a dosing regimen of 500-875 mg orally twice daily for outpatient treatment 1, 2, 4
The American College of Emergency Physicians suggests that the duration of treatment should be 7-14 days depending on severity, or 3-5 days for prophylaxis in high-risk wounds 5

The Clinical Infectious Diseases guidelines state that dicloxacillin and other penicillinase-resistant penicillins have poor in vitro activity against Pasteurella multocida and should be avoided as monotherapy for animal bites 1
The Centers for Disease Control and Prevention note that Pasteurella species are isolated from 50% of dog bite wounds and 75% of cat bite wounds, making coverage essential 1

The World Health Organization recommends doxycycline 100 mg twice daily as an alternative regimen for animal bite infections, with excellent activity against Pasteurella multocida, though some streptococci may be resistant 2, 4
The European Society of Clinical Microbiology and Infectious Diseases suggests fluoroquinolones (ciprofloxacin, levofloxacin, moxifloxacin) plus metronidazole or clindamycin for anaerobic coverage as an alternative regimen 1, 4

The American College of Surgeons notes that failure to recognize the polymicrobial nature of animal bite infections leads to inadequate treatment, with animal bite wounds yielding an average of 5 different bacterial species, and 60% containing mixed aerobic and anaerobic bacteria 1, 3, 5
The Infectious Diseases Society of America states that cat bites have higher infection rates (30-50%) compared to dog bites (5-25%) and greater prevalence of anaerobes (65% vs 50%) 1, 5

The Society of Critical Care Medicine recommends ampicillin-sulbactam 1.5-3.0 g every 6-8 hours or piperacillin-tazobactam 3.37 g every 6-8 hours for hospitalized patients or severe infections 2, 4