Capnocytophaga canimorsus and Dog Bites

Capnocytophaga canimorsus is a Gram-negative bacillus (rod-shaped) bacterium, in which it can harbor potentially dangerous complication if an asplenic patient was bitten by a dog[1]. This bacterium actually can be found on not just dog bites, but can also be found on those bitten by cats[2]. Clinical infections by C. canimorsus generally appear as fulminant septicemia, peripheral gangrene or meningitis[2].

Management of dogbite is as follows:
In initial treatment, thorough history should be taken with risk of rabies infection (can lead to serious manifestation), the time of the injury, whether the animal was provoked, and the general health, immunization status and current location of the animal, tetanus immunization status, current medications and allergies must be noted in the record. During the physical examination, the measurement and classification of the wound (laceration, puncture, crushing or avulsion), and the range of motion of the affected and adjacent areas should be documented. Nerve, vascular and motor function, including pertinent negative findings, should be recorded. Diagrams and photographs are useful, especially in cases with irregular wounds or signs of infection, and in cases that may involve litigation, such as a wound inflicted by an unleashed dog.

Interestingly, only 15 to 20 percent of dog bite wounds become infected, with Pasteurella multocida and Staphylococcus aureus are the most common aerobic organisms, occurring in 20 to 30 percent of infected dog bite wounds. C. canimorsus is aerobic organism too itself. Treatment with prophylactic antibiotics for three to seven days is appropriate for dog bite wounds, unless the risk of infection is low or the wound is superficial. Amoxicillin-clavulanate potassium (Augmentin) is the antibiotic of choice for a dog bite. For patients who are allergic to penicillin, doxycycline (Vibramycin) is an acceptable alternative, except for children younger than eight years and pregnant women. Erythromycin can also be used, but the risk of treatment failure is greater because of antimicrobial resistance. Other acceptable combinations include clindamycin (Cleocin) and a fluoroquinolone in adults or clindamycin and trimethoprim-sulfamethoxazole (Bactrim, Septra) in children. When compliance is a concern, daily intramuscular injections of ceftriaxone (Rocephin) are appropriate[3].

Specifically for C. canimorsus, you can visit the site: http://hopkins-abxguide.org/pathogens/bacteria/capnocytophaga_canimorsus.html?&contentInstanceId=255804

Prevention is very important to prevent from being bitten by dogs[4].
Before you bring a dog into your household:
-Consult with a professional (e.g., veterinarian, animal behaviorist, or responsible breeder) to learn what breeds of dogs are the best fit for your household.
-Dogs with histories of aggression are not suitable for households with children.
-Be sensitive to cues that a child is fearful or apprehensive about a dog. If a child seems frightened by dogs, wait before bringing a dog into your household.
-Spend time with a dog before buying or adopting it. Use caution when bringing a dog into a household with an infant or toddler.

If you decide to bring a dog into your home:
-Spay/neuter your dog (this often reduces aggressive tendencies).
-Never leave infants or young children alone with a dog.
-Don’t play aggressive games with your dog (e.g., wrestling).
-Properly socialize and train any dog entering your household.
-Teach the dog submissive behaviors (e.g., rolling over to expose the abdomen and giving up food without growling).
-Immediately seek professional advice (e.g., from veterinarians, animal behaviorists, or responsible breeders) if the dog develops aggressive or undesirable behaviors.

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References:
1. Janda JM, Graves MH, Lindquist D, Probert WS. Diagnosing Capnocytophaga canimorsus infections. Emerg Infect Dis [serial on the Internet]. 2006 Feb [date cited]. Available from http://www.cdc.gov/ncidod/EID/vol12no02/05-0783.htm
2. Mally M, Shin H, Paroz C, Landmann R, Cornelis GR (2008) Capnocytophaga canimorsus: A Human Pathogen Feeding at the Surface of Epithelial Cells and Phagocytes. PLoS Pathog 4(9): e1000164. Available from : http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1000164
3. R. JOHN PRESUTTI. Prevention and Treatment of Dog Bites. American Academy of Family Physicians. 2001, April 15. Available from: http://www.aafp.org/afp/2001/0415/p1567.html
4. Centers for Disease Control and Prevention. Dog Bite Prevention. Atlanta. May 14, 2009[last reviewed]. Available from: http://www.cdc.gov/homeandrecreationalsafety/dog-bites/biteprevention.html