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Are antibiotics indicated following human bites?

Three Part Question

In [healthy adults sustaining a human bite] do [prophylactic antibiotics] reduce [the incidence of infection]?

Clinical Scenario

A healthy 25-year-old man involved in an altercation with another man sustains a bite wound on the arm and presents to the Accident and Emergency Department. The wound is thoroughly cleaned and no signs of infection are present. You wonder whether prophylactic antibiotics are indicated to reduce the risk of wound infection in this patient.

Search Strategy

MEDLINE (1996- Nov 03) & EMBASE (1980-Nov 03)
Cochrane database Edition 1 2005.
Medline and Embase:
[human or exp Bites, Human/] and [ or exp Penicillins/ or or exp Anti-Bacterial Agents/ or or ERYTHROMYCIN/ or or exp Amoxicillin-Potassium Clavulanate Combination/ or or exp CEPHALOSPORINS/] and wound or exp Wound Infection/ or exp Postoperative Complications/ or exp Bacterial Infections/ or exp Surgical Wound Infection/ or infection] Limit to human and English
"Human Bites"

Search Outcome

Medline and Embase: 89 papers, two of which were relevant to the original question.
Cochrane:32 citations. One review on mammalian bites. No new relevant papers on human bites found.

Relevant Paper(s)

Author, date and country Patient group Study type (level of evidence) Outcomes Key results Study Weaknesses
Zubowicz VN & Gravier M
48 patients with early (<24hr) human bites to the handProspective randomized controlled trialInfection rate: Placebo v oral cephalosporin v IV cephalosporin + penicillin GInfection rate: 46.7% placebo v 0% oral / IV antibiotic (P < 0.05)Small study population within each group
Broder J
127 patients with early (<24hr) superficial human bites excluding to the hand, feet or skin overlying jointsProspective double-blind placebo-controlled trialInfection rate: Placebo v oral cephalosporin/penicillinInfection rate: 1.6% placebo v 0% antibiotic (P > 0.05)Only investigated low risk bites


The first study showed a clear benefit of giving prophylactic antibiotics for human bites to the hand. The second study did not demonstarte any significant reduction of infection rate with antibiotics for low risk superficial human bites, which were defined as those bites that penetrated only the epidermis and did not involve the hands, feet, or skin overlying joints or cartilaginous structures. It may be that antibiotic treatment of the low risk bites described is unnecessary. Until further studies demonstrate no reduction in infection rates for human bites, antibiotics should be given to all patients except those presenting with superficial bites outwith the areas described above. No PRCTs have investigated which particular antibiotics should be prescribed, and therefore antibiotic choice should follow local guidelines until studies have shown a particular antibiotic to be the most effective.

Clinical Bottom Line

Prophylactic antibiotics should be given to all patients with human bites to the hands, feet, and skin overlying joints or cartilaginous structures, and to all patients with bites that penetrate deeper than the epidermal layer.

Level of Evidence

Level 2 - Studies considered were neither 1 or 3.


  1. Zubowicz VN & Gravier M Management of early human bites of the hand: a prospective randomized study Plastic and reconstructive surgery 1991;88(1):111-114
  2. Broder J, Jerrard D, Olshaker J Witting M. Low risk infection in selected human bites treated without antibiotics. American Journal of Emergency Medicine. 2004;22(1):10-13