Antibiotics for reducing the rate of infection after bites by mammals such as humans

Medeiros IM, Saconato H

Published Online:

July 16, 2008

Bite wounds may become infected due to the transfer of bacteria from the mouth of mammals into the skin. There was a decrease in the risk of developing an infection after a human bite when given antibiotics. Antibiotics also decreased the chance of developing a wound infection after a bite on the hand. Further studies are required to confirm these findings.

Abstract (click to read)

Background:

Bites by mammals are a common problem and they account for up to 1% of all visits to hospital emergency rooms. Dog and cat bites are the most common and people are usually bitten by their own pets or by an animal known to them. School-age children make up almost a half of those bitten. Prevention of tetanus, rabies and wound infection are the priorities for staff in emergency rooms. The use of antibiotics may be useful to reduce the risk of developing a wound infection.

Objectives:

To determine if the use of prophylactic antibiotics in mammalian bites is effective in preventing bite wound infection.

Search strategy:

Relevant RCTs were identified by electronic searches of MEDLINE, EMBASE, LILACS and the Cochrane Controlled Trials Register databases in November 2000.

Selection criteria:

We included randomised controlled trials which studied patients with bites from all mammals. Comparisons were made between antibiotics and placebo or no intervention. The outcome of interest was the number of infections at the site of bite.

Data collection and analysis:

Two reviewers extracted the data independently. All analyses were performed according to the intention-to-treat method.

Main results:

Eight studies were included. The use of prophylactic antibiotics was associated with a statistically significant reduction in the rate of infection after bites by humans. Prophylactic antibiotics did not appear to reduce the rate of infection after bites by cats or dogs. Wound type, e.g. laceration or puncture, did not appear to influence the effectiveness of the prophylactic antibiotic. Prophylactic antibiotics were associated with a statistically significant reduction in the rate of infection in hand bites (OR 0.10, 95% CI 0.01 to 0.86; NNT = 4, 95% CI 2 to 50).

Authors' conclusions:

There is evidence from one trial that prophylactic antibiotics reduces the risk of infection after human bites but confirmatory research is required. There is no evidence that the use of prophylactic antibiotics is effective for cat or dog bites. There is evidence that the use of antibiotic prophylactic after bites of the hand reduces infection but confirmatory research is required.

This record should be cited as:

Medeiros IM, Saconato H. Antibiotic prophylaxis for mammalian bites. Cochrane Database of Systematic Reviews 2001, Issue 2. Art. No.: CD001738. DOI: 10.1002/14651858.CD001738

Assessed as up to date:

February 11, 2001

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Primary Review Group:

Wounds Group

PEARLS - Practical Evidence About Real Life Situations (click to read)

Clinical question:

Do prophylactic antibiotics in mammalian bites prevent wound infection?

Bottom line:

Prophylactic antibiotics may reduce the rate of infection after bites by humans NNT =2 (based on 1 study) and after animal bites on the hand (NNT 3 to 7) based on 3 studies. Bites on head and trunk did not seem to benefit from antibiotics.

Caveat:

Several studies included in the review were small, one involving only 12 patients. Different antibiotics were used in the studies, ranging from penicillin V to dicloxacillin.

Context:

Bites by mammals are a common problem, accounting for up to 1% of all visits to hospital emergency rooms. Dog and cat bites are most common, and school-age children make up almost half of those bitten

Cochrane Systematic Review:

Medeiros I, Saconato H. Antibiotic prophylaxis for mammalian bites. Cochrane Database of Systematic Reviews 2001, Issue 2. Art. No.: CD001738. DOI: 10.1002/14651858.CD001738. Note: this review contains 8 studies with 522 participants.

Authored by:

Brian R McAvoy

Cochrane Primary Health Care Field

Health topics:

Infectious disease > Zoonotic & rare diseases > Animal bite

Skin > Wounds > Bites

Wounds > Bites

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Antibiotics for reducing the rate of infection after bites by mammals such as humans

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