During an outbreak investigation of acute watery diarrhoea in a village following flooding, stool cultures yield comma-shaped, gram-negative organisms growing on TCBS medium producing yellow colonies. Which species is most likely?
- A Vibrio parahaemolyticus
- B Aeromonas hydrophila
- C Vibrio cholerae El Tor ✓
- D Enterotoxigenic E. coli
Correct answer: C. Vibrio cholerae El Tor
Explanation
Vibrio cholerae produces yellow colonies on TCBS (Thiosulphate Citrate Bile Salts Sucrose) agar due to sucrose fermentation, while Vibrio parahaemolyticus produces blue-green (sucrose non-fermenting) colonies. V. cholerae El Tor biotype is responsible for the ongoing (7th) pandemic and causes the classic rice-water stools seen in epidemic cholera, often triggered by flood-related contamination of water supplies.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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