Which of the following is not on the CDC list of potential Category B bioterrorism agents?

• A. Burkholderia mallei
• B. Coxiella burnetii
• C. E. coli 0157:H7
• D. Francisella tularensis

Answer: (D)

The main idea is how the CDC groups bioterrorism threats by how dangerous and how easily they spread. Francisella tularensis, which causes tularemia, is classified as a Category A agent because it can cause severe illness and has the potential for rapid, widespread impact with relatively few organisms needed to cause infection, making it a high-priority threat that requires the most preparedness. It is not placed in Category B, which includes agents considered significant but not at that highest level of priority. The other listed organisms—Coxiella burnetii (Q fever), Burkholderia mallei (glanders), and Escherichia coli O157:H7—are categorized as Category B because they pose serious public health risks but are not deemed as high-priority as Tularemia. So the agent not on the Category B list here is Francisella tularensis.