A severely burned firefighter develops a rapidly disseminating bacterial infection while hospitalized. Green pus is noted in the burned tissue and cultures of both the tissue and blood yield small oxidase-positive gram-negative rods. Which of the following statements most accurately conveys information about this organism?

• A. Endotoxin is the only virulence factor known to be produced by these bacteria
• B. Humans are the only known reservoir hosts for these bacteria
• C. The bacteria are difficult to culture because they have numerous growth requirements
• D. These are among the most antibiotic-resistant of all clinically relevant bacteria