American Board of Internal Medicine (ABIM) Certification Practice Exam

Which organism is linked to infections from contact with dogs?

1. Streptococcus pneumoniae

2. Pasteurella multocida

3. Capnocytophaga canimorsus

4. Mycobacterium abscessus

The correct answer is: Capnocytophaga canimorsus

Capnocytophaga canimorsus is indeed associated with infections from contact with dogs. This organism is part of the normal oral flora of dogs and cats, and human infections typically occur following a bite or close contact with an infected animal. In immunocompromised individuals or those without a spleen, infections can lead to serious complications, including septicemia and disseminated intravascular coagulation. For context, while Streptococcus pneumoniae is a major cause of pneumonia and meningitis, it is not specifically linked to dog contact. Pasteurella multocida is another organism that can be associated with animal bites, particularly from cats, and can cause soft tissue infections, but it is less commonly linked to dog bites compared to Capnocytophaga canimorsus. Mycobacterium abscessus is primarily associated with soft tissue infections, often in the context of immunocompromised individuals or following procedures like surgery or injections, and does not have a notable association with infections from dog contact. Thus, Capnocytophaga canimorsus is the organism specifically linked to infections due to contact with dogs.