Bite wound infections

Abstract

Patients with mammalian bite wounds account for hundreds of thousands of emergency department, urgent care center, and physician office visits in the United States each year. The types of wounds encountered by physicians range from insignificant scratches to life-threatening neck and facial injuries. Infectious complications of bite wounds are common, and the consequences of these infections are significant and sometimes disabling. This article reviews the infectious complications of cat, dog, and human bite wounds. The prevention of tetanus and rabies virus infection, the appropriate antimicrobial treatment of bacterial infections, and the frequent need for surgical consultation and intervention are emphasized.

Animal and Human Bite Wounds

“…Reported infection rates are given in Box 2. In general, 10-20% of bite wounds become infected, including 30-50% of cat bites, 5-25% of dog bites (30)(31)(32)(33), and 20-25% of human bites (4,14,19,30). The risk of infection depends on the nature and site of the wound as well as on individual patient characteristics and the species by which he or she was bitten (Box 3).…”

“…N eonates and infants are at higher risk of infection than older children, adolescents, or adults. The patients at highest risk are those with immune dysfunction of any cause, e.g., AIDS, hepatopathy (alcoholism), asplenism, cancer, neutropenia, diabetes, and treatment with corticosteroids or immunosuppressants (26,(31)(32)(33). Persons without any predisposing factors can also suffer from severe or lethal infections in bite wounds (34, e8-e10).…”

“…30-60% of infections in bite wounds are mixed aerobicanaerobic infections (30,33,35) derived from the oral flora of the biting animal or, more rarely, from the victim's skin flora or the environment (25,30,32). On average, a cat or dog bite wound contains 2-5 different species of bacteria (32,35,36). The number of pathogenic species in the wound depends on its type: 7.5 (median) in abscesses, 5 in purulent wound secretions, and 2 in non-purulent wounds (36).…”

“…Streptococci can be isolated from 50% of human bite wounds, Staphylococcus aureus from 40%, and Eikenella corrodens from 30%. It is commonly accepted that the pathogen most often leading to infection is E. corrodens, a Gram-negative microaerophilic bacillus (30,32). Human bites can transmit HBV, HCV, and HIV; post-exposure prophylaxis should be considered in every case (16).…”

“…The manifestations of infection arise within 12-24 hours with P. multocida and somewhat later with other pathogens. C. canimorsus infection sometimes does not become symptomatic until 5-8 days have elapsed (32,33).…”