Which organism is oxidase positive and known for causing cholera?

• A. Vibrio cholerae
• B. Pseudomonas aeruginosa
• C. Campylobacter jejuni
• D. Neisseria gonorrhoeae

Answer: (A)

The key idea is identifying oxidase-positive organisms and recognizing which one is linked to cholera. Vibrio cholerae is the organism that both tests oxidase-positive and is known for causing cholera. It’s a curved, gram-negative rod that is oxidase positive, and infection with it leads to the classic rice-water diarrhea due to the cholera toxin. The other organisms listed can be oxidase positive as well but are associated with different diseases (for example, Pseudomonas with a range of infections, Campylobacter with gastroenteritis, and Neisseria with gonorrhea), so they don’t fit the combination of cholera and oxidase positivity.