Friday, January 12, 2024

Shigella soni color on MacConkey and EMB is.. Colorless

Shigella soni color on MacConkey and EMB is:

  • A- Red
  • B- Pink
  • C- Colorless
  • D- Black

Shigella sonnei, a Gram-negative bacterium that causes shigellosis, will typically exhibit a C. Colorless appearance on both MacConkey and EMB agar plates.

Here's why:

- MacConkey agar:

Shigella sonnei doesn't ferment lactose, a sugar present in the media. Therefore, it won't produce enough acid to change the pH indicator and remain colorless on MacConkey agar.

- EMB agar:

This media also relies on lactose fermentation and the presence of specific dyes to differentiate bacteria. Shigella sonnei, again due to its lack of lactose fermentation, won't produce the characteristic green metallic sheen associated with lactose-fermenting bacteria on EMB agar and remain colorless.

Other Options:

While other options might be applicable to different bacteria:

A. Red:

This could describe lactose-fermenting bacteria on MacConkey agar, which turn the media red due to acid production.

B. Pink:

Some bacteria may display a pink coloration on EMB agar due to their ability to ferment other sugars present in the media.

D. Black:

This color is typically not seen on either MacConkey or EMB agar and might indicate the presence of other bacterial types or contamination.

Therefore, based on its non-lactose fermenting nature, Shigella sonnei appears colorless on both MacConkey and EMB agar plates. This characteristic aids in its identification and differentiation from other bacteria during laboratory cultures.

Remember, this information is for educational purposes and shouldn't be used for self-diagnosis or treatment. Always consult a healthcare professional for proper medical advice and diagnosis.