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Bites - human and animal - Management
Which antibiotic should I give to someone with a human bite?

  • For both prophylaxis and treatment of an infected human bite prescribe a 7-day course of co-amoxiclav.
  • For people who are allergic to penicillin prescribe a 7-day course of:
    • Metronidazole plus doxycycline, or
    • Metronidazole plus erythromycin, or
    • Metronidazole plus clarithromycin.
Basis for recommendation
  • These recommendations are based on expert opinion published in the medical literature [HPA, 2005b; HPA, 2006a].
  • There is limited evidence that antibiotics prevent infections after a human bite.
  • More than 42 different species of bacteria have been isolated from the human mouth, and up to 190 if gingivitis or periodontitis are present. The most common organisms in human bites include Streptococcus spp, Staphylococcus aureus, Haemophilus spp, Eikenella corrodens, and Bacteroides spp and other anaerobes. E. corrodens has been found in 25% of human bites to the hand [Smith et al, 2000; HPA, 2005b; Morgan, 2005].
  • Co-amoxiclav:
    • Co-amoxiclav is recommended because it is a broad-spectrum antibiotic and effective against the most commonly isolated organisms from human bites including alpha- and beta-haemolytic streptococci, S. aureus, S. epidermis, corynebacteria, and E. corrodens.
  • Metronidazole plus erythromycin or clarithromycin:
    • Metronidazole (in addition to tetracyclines or erythromycin) covers beta-lactamase-producing anaerobes.
    • Erythromycin has good activity against staphylococci and streptococci (the most common pathogens).
    • Clarithromycin may be more suitable if erythromycin cannot be tolerated due to adverse effects.

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