Bacteria Cultured from a Bear Bite

One of the dangers of an animal bite (aside from the trauma of the bite itself) is the possibility of infection due to flora in the mouth of the animal. If an infection does develop from an animal bite, knowing the flora present is helpful in choosing antibiotics that will be effective. Most animals that interact with humans (cats, dogs, etc) have well-defined flora. Less is known about other animals, such as bears, that rarely bite humans.

A case report from 2004 describes the bacteria cultured from a bite wound inflicted on a hunter by a grizzly bear in Canada. Cultures taken about 12 hours after the bite grew Serratia fonticola, Serratia

marcescens (used to draw a raptor, right), Aeromonas hydrophila, Bacillus cereus, and Enterococcus durans. No anaerobes were isolated from the wound. The patient was given 1 week of piperacillin-tazobactam therapy followed by  amoxicillin-clavulanate and ciprofloxacin for 3 weeks as prophylactic treatment.

Infection after a bear bite is common, with around 44% of patients showing infection. However, few of these bite wounds have been cultured for identification of flora, so there is limited knowledge of what is common or what antimicrobials are appropriate for treatment. Some scientists hypothesize that oral flora of bears will be similar to that of dogs, as well as being highly variable depending on the foraging environment and habits of a particular bear.

More information about the patient and his clinical outcomes can be found here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC446265/#__ffn_sectitle