Which organism is identified by yellow colonies on TCBS agar and oxidase positive?

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Multiple Choice

Which organism is identified by yellow colonies on TCBS agar and oxidase positive?

TCBS agar is designed to selectively grow Vibrio species and to differentiate them by how they ferment the sugar in the medium. When a bacterium ferments sucrose on this medium, acid is produced and the indicator turns yellow. Among Vibrio, cholerae is a classic sucrose fermenter, so it forms yellow colonies on TCBS. At the same time, it is oxidase positive, meaning it has the cytochrome c oxidase enzyme detectable by an oxidase test. Enteric pathogens like E. coli, Salmonella, and Shigella are typically oxidase negative and do not produce the yellow sucrose-fermenting colonies on TCBS, so they don’t match both features.

TCBS agar is designed to selectively grow Vibrio species and to differentiate them by how they ferment the sugar in the medium. When a bacterium ferments sucrose on this medium, acid is produced and the indicator turns yellow. Among Vibrio, cholerae is a classic sucrose fermenter, so it forms yellow colonies on TCBS. At the same time, it is oxidase positive, meaning it has the cytochrome c oxidase enzyme detectable by an oxidase test. Enteric pathogens like E. coli, Salmonella, and Shigella are typically oxidase negative and do not produce the yellow sucrose-fermenting colonies on TCBS, so they don’t match both features.

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