Prophylactic oral antibiotics for low-risk dog bite wounds

The use of prophylactic antibiotics in the initial treatment of noninfected dog bite wounds is controversial. All patients with noninfected dog bite wounds who presented to our emergency department (ED) over a two-year period were considered for entry into a randomized prospective study. Patients were excluded from the study if they had any high-risk criteria for infection: puncture wounds, hand or foot wounds, wounds greater than 12 hours old, a history of immunocompromising disorders, or the use of immunosuppressive drugs. Patients in the antibiotic group (n = 89) were treated with local wound care and given either dicloxacillin, cephalexin, or erythromycin orally for seven days. Patients in the control group (n = 96) received local wound care only. All patients had their wounds irrigated with a 1% povidone-iodine solution and debrided and sutured if clinically indicated. All patients were subsequently reevaluated for clinical signs of wound infection. The groups were similar in age, sex, time of delay in seeking treatment, anatomic sites of wounds, depths and types of wounds, and number of wounds requiring suturing. The wound infection rates for the antibiotic and control groups were 1.1 and 5.1%, respectively. This difference was not significant (P = 0.212). There were 36 wounds in the antibiotic group and 37 wounds in the control group that were full thickness. The infection rates for these wounds were 2.8 and 13.5%, respectively. This was not statistically significant (P = 0.132). This study suggests that prophylactic oral antibiotics in low-risk dog bite wounds are not indicated.