Annually, in the United States, more than 5 million animal and untold numbers of human bite wounds occur and account for 10 000 persons hospitalized and 1% (300 000) of all emergency department visits. Patients with bite wounds are also commonly seen as outpatients in primary care physician and specialist (orthopedics, plastic/hand surgery, infectious diseases physicians) offices. Some patients will attempt to conceal the nature of the injury with human bite wounds. The bacteriology of these wounds is diverse and comprises oral flora organisms, both aerobic and anaerobic, of the biting animal/human, the victim's skin flora, and occasionally environmental isolates.

ANIMAL BITES

Microbiology

An extensive number of bacterial species are isolated from infected dog and cat bite wounds. Pasteurella species, especially Pasteurella multocida and Pasteurella septica, will be present in 75% and 65% of cat bite and dog bite wounds, respectively. Anaerobes will be present in 50% of dog bite wounds and 67% of cat bite wounds. Streptococci, excluding group A β-hemolytic streptococci (Streptococcus pyogenes) are present in 46% of dog and cat bite wounds, whereas Staphylococcus aureus is present in 20% of dog bites but only 4% of cat bites. Streptococcus pyogenes (group A), if present, usually comes from the victim's skin because it is rarely isolated from dog oral flora. Streptococcus aureus is also a secondary invader originating as skin flora. Capnocytophaga canimorsus is an uncommon wound isolate but has been associated with bacteremia, some fatal, in asplenic and cirrhotic patients.