A culture from a dog bite wound grew a gram-negative, slender rod that is a facultative anaerobe. What is the most likely identification?

The identification of the organism as Capnocytophaga canimorsus is appropriate given its association with dog bites and its characteristics as a slender, gram-negative rod. This bacterium is part of the normal flora in the mouths of dogs and can be transmitted to humans through bites or scratches. Capnocytophaga canimorsus is particularly known for causing wound infections and more severe systemic infections in humans, primarily in those with compromised immune systems.

In the context of this specific clinical scenario, the growth from a dog bite wound, alongside the description of it being a facultative anaerobe, aligns well with the known behaviors and characteristics of Capnocytophaga canimorsus. This bacterium's ability to survive in both aerobic and anaerobic environments further supports its identification.

Other options, while also being gram-negative rods, do not have the same strong association with dog bites or the specific characteristics noted in this case. For example, Pseudomonas aeruginosa is more commonly found in moist environments and is often associated with infections in immunocompromised patients. Acinetobacter baumannii is typically linked to hospital-acquired infections rather than animal bites. Proteus mirabilis is often associated with urinary tract infections and does not