If a bacterium utilizes lactose or sucrose, what will the TSI reaction look like?
A) Alkaline/acid
B) Alkaline/alkaline
C) Acid/acid
D) Acid/alkaline

Question

Quizplus · Accepted Answer

The TSI (Triple Sugar Iron) test is designed to differentiate bacteria based on their ability to reduce sulfur and ferment carbohydrates. If a bacterium can utilize lactose or sucrose, it will ferment these sugars, producing acid both in the slant (surface) and the butt (bottom) of the medium, leading to an acid/acid (A/A) reaction, which is indicated by yellow coloration in both parts.

If a Bacterium Utilizes Lactose or Sucrose, What Will the TSI