Question

what is the full name of the media used to observe the results in this image?

nitrate broth
tryptic soy broth
fluid thioglycollate media
semi-solid nutrient agar with ttc

Explanation:

Identify the visual characteristics of the tube

The image shows a tube containing a semi-solid medium with a red/purple growth pattern along a central stab line. The red color is due to the reduction of triphenyltetrazolium chloride (TTC) by metabolically active bacteria, which turns from colorless to insoluble red formazan.

Evaluate the given options

• Nitrate broth: Used to determine the ability of an organism to reduce nitrate to nitrite. It is a liquid broth and does not show a localized stab line with TTC.
• Tryptic soy broth: A general-purpose liquid medium used for cultivation, which does not contain agar or TTC.
• Fluid thioglycollate media: Used to test the oxygen requirements of organisms. While it has a slight agar content to create an oxygen gradient, it does not typically use a TTC indicator to show a red stab line for motility.
• Semi-solid nutrient agar with TTC: Specifically designed for motility testing. The semi-solid agar concentration allows motile bacteria to swim away from the stab line, and the addition of TTC makes the bacterial growth highly visible as a red color.

Answer:

• Nitrate broth
• Tryptic soy broth
• Fluid thioglycollate media
• Semi-solid nutrient agar with TTC (Correct answer)