A patient presents with severe watery diarrhea after consuming contaminated shellfish. A stool sample is cultured on a medium containing thiosulfate, citrate, bile salts, and sucrose. The organism grows as yellow colonies. Which pathogen is most likely identified?
- A Vibrio parahaemolyticus
- B Vibrio cholerae ✓
- C Salmonella typhi
- D Shigella dysenteriae
Correct answer: B. Vibrio cholerae
Explanation
Thiosulfate-citrate-bile salts-sucrose (TCBS) agar is selective for Vibrio species. Vibrio cholerae ferments sucrose, producing yellow colonies. Vibrio parahaemolyticus does not ferment sucrose and forms green colonies. Salmonella and Shigella do not grow well on TCBS.
Reference: Ananthanarayan and Panicker's Textbook of Microbiology, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.