A mailman gets a severe bite wound from a pit bull. The wound is cleansed and he receives a booster injection of tetanus toxoid and an injection of penicillin G. Several days later, the wound is inflamed and purulent. The exudate is cultured on blood agar and yields gram-negative rods. Antibiotic sensitivity tests are pending. Which of the following is the most likely pathogen?

A. Bartonella henselaeB. Brucella canisC. Clostridium tetaniD. Pasteurella multocidaE. Toxocara canis

The correct answer is: option D. Pasteurella multocida

Explanation:

Mailman is more likely to infected by the Pasteurella multocida as these pathogen infects the human and other mammals by cat or dog bites and can grow in the laboratory for the test.

On the other hand, Bartonella henselae infect others by cat's scratch disease, usually histologically diagnoses, as not easily grow. Brucella Canis do not infect humans but dogs only and infection takes place through ingestion rather bite.

Toxocara canis is a roundworm parasite that causes infections in dogs, humans can also be infected by accident but tetani treat these infections.

Thus, the correct answer is : option D.