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Three Part Question

In [healthy adults with dog bite wounds] do [prophylactic antibiotics] reduce [the incidence of wound infection]?

Clinical Scenario

A 30 year old man attends the emergency department having been bitten by a dog 4 hours previously. He has puncture wounds and a 1 cm laceration on his forearm. His wounds are thoroughly cleaned and a dressing applied. You want to know whether to prescribe antibiotics as well.

Search Strategy

Medline 1966-06/98 using the OVID interface.
({[exp antibiotics OR antibiotic$ ti.ab.sh] AND [exp bites and stings OR bite$ ti.ab.sh]} AND [exp dogs OR dog$ ti.ab.sh OR canine$ ti.ab.sh]) LIMIT to human AND english language.

Search Outcome

120 papers found of which 1 was a meta-analysis of 8 other papers (RCTs) which were also found. 111 papers were discarded as either irrelevant or of insufficient quality for inclusion.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Cummings P. 1994. USA.	8 randomised controlled trials.	Meta-analysis.	Wound infection	Relative risk of infection in the treated (antibiotic) group was 0.56.	This is not a systematic review.
			-	14 patients must be treated to prevent 1 infection

Comment(s)

All the studies used oral antibiotics - mainly penicillin or penicillinase resistant penicillin. This paper accounts for the variable quality of the trials that were included. The test for heterogenicity of the relative risks was not significant (P = 0.36). This analysis does not address the issues of which antibiotic to prescribe, or which wounds are at higher risk of infection.

Clinical Bottom Line

Use of oral antibiotics for all types of dog bite wounds reduces the risk of infection by nearly half. A prescribing policy that limits antibiotics to higher risk wounds may be effective.

References

1. Cummings P. Antibiotics to prevent infection in patients with dog bite wounds: a meta-analysis of randomized trials. Ann Emerg Med 1994;23(3):535-540.