Question

As a means to confirm diagnosis, TCBS agar (Thiosulfate-citrate-bile salts-sucrose agar) is used to grow Vibrio cholerae from patient samples The recipe for this growth media is shown below. Based on this information, which of the following statements accurately describe this media? Select all that apply. (NCLEX-HESI-TEAS style)

This media is considered a complex agar.

This agar is selective.

Bromothymol blue and thymol blue contribute to this agar's use as a differential media.

Prior to inoculation, the agar is likely yellow.

Answer 1

Nutrient agar is a simple agar. It contain peptone, sodium chloride and water. It allows only the growth of non-fastidious organism.

TCBS agar is a complex agar as apart from the contains of simple agar, it contains additional substances and it allows growth of fastidious organism.

So option A is correct.

This agar only allow the growth of vibrio sp. and inhibit the growth of other intestinal bacteria. So it is a selective media.

Option B is correct.

Bromothymol blue and thymol blue act as a pH indicator & makes the media, differential media.

Vibrio cholera produces yellow colour colony on TCBS agar and Vibrio parahemolyticus produce green colour colony.

So option C is correct.

Prior to inoculation, the agar is green in colour.

So option D is wrong.

Answer- Option A,B &C.

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