Which statement about Campylobacter jejuni is true?

• A. Catalase negative
• B. Isolated best at 24°C
• C. Hydrogen sulfide positive
• D. A leading cause of bacterial diarrhea worldwide

Answer: (D)

Campylobacter jejuni is a major cause of bacterial gastroenteritis worldwide. It is a microaerophilic organism that grows best under low-oxygen conditions at a relatively warm temperature, around 42°C, and it is oxidase- and catalase-positive. It does not produce hydrogen sulfide on standard media. Because of its epidemiology—transmitted commonly via undercooked poultry, unpasteurized dairy, and contaminated water—it consistently ranks as a leading cause of bacterial diarrhea across many regions. These points explain why the statement describing it as a leading cause of bacterial diarrhea worldwide is the correct one, while the other attributes (growth optimally at 24°C, catalase negativity, or hydrogen sulfide production) do not fit Campylobacter jejuni’s known characteristics.