Source: Fagan S, Hess D. Skin and soft tissue infections. In: DiPiro JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey LM, eds. Pharmacotherapy: A Pathophysiologic Approach. 10th ed. New York, NY: McGraw-Hill; 2017. https://accesspharmacy.mhmedical.com/content.aspx?bookid=1861§ionid=146071658. Accessed February 23, 2019.
Infections in bite wounds are typically caused by mouth flora from the animal or human bites, in addition to the victim’s own skin flora. [Table 1]
Most infections are polymicrobial:
Pasteurella is most common isolate from both dogs and cat bites.
Bartonella henselae can cause cat scratch disease.
Rabies is associated with dog bites (mostly in developing countries).
Eikenella corrodens is found in human bite wounds.
TABLE 1Bacterial Isolates from Infections in Animal and Human Bite Wounds ||Download (.pdf) TABLE 1 Bacterial Isolates from Infections in Animal and Human Bite Wounds
|Organisms ||Percentage of Isolates |
|Dog and Cat ||Human |
|Aerobes ||74–90 ||44 |
|Pasteurella spp. ||50–75 ||— |
|Streptococcus spp. ||46–50 ||52–84 |
|S. anginosus ||— ||52 |
|S. mitis ||22 ||12 |
|S. pyogenes ||12 ||14 |
|S. mutans ||12 ||2 |
|Staphylococcus spp. ||35–46 ||54 |
|S. aureus ||20 ||30 |
|S. epidermidis ||18 ||22 |
|Neisseria spp. ||32–35 ||4 |
|Moraxella spp. ||10–35 ||2 |
|Corynebacterium spp. ||12–28 ||12 |
|Enterococcus spp. ||10–12 ||6 |
|Bacillus spp. ||8–11 ||— |
|Eikenella corrodens ||2 ||30 |
|Enterobacteriaceae ||6–12 ||8–15 |
|Anaerobes ||50–70 ||40–90 |
|Fusobacterium spp. ||32–33 ||32–34 |
|Porphyromonas spp. ||28–30 ||2 |
|Bacteroides spp. ||18–28 ||4 |
|Prevotella spp. ||19–28 ||22–36 |
|Propionibacterium spp. ||18–20 ||4 |
|Peptostreptococcus spp. ||8–16 ||22 |
|Veillonella spp. ||2 ||24 |
|Mixed aerobic and anaerobic ||50–75 ||40–66 |
Potential for infection from an animal bite is extremely high due to the pressure that can be exerted during the bite, and the vast number of potential pathogens that make up the normal oral flora of animals.
Cats’ teeth are slender and extremely sharp, and can easily penetrate into bones and joints, which can lead to septic arthritis and osteomyelitis.
Human bites are more serious and more prone to infection than animal bites, specifically clenched-fist injuries.
Dog bites account for 60% of all animal bite, with cat bites accounting for 20%.
The rate of dog bite related injuries is highest in children aged 5–9 years.
Most dog bites are to the extremities, with the majority of bites to children <5 years of age to the face and neck.