🦠microbiology review

Cetrimide agar

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

Cetrimide agar is a selective medium used for the isolation and identification of Pseudomonas aeruginosa, a common pathogen in skin and eye infections. It contains cetrimide, which inhibits the growth of other bacteria while promoting the production of characteristic pigments by Pseudomonas aeruginosa.

5 Must Know Facts For Your Next Test

  1. Cetrimide agar is specifically designed to isolate Pseudomonas aeruginosa from clinical samples.
  2. The medium contains cetrimide, which selectively inhibits non-Pseudomonas bacteria.
  3. Pseudomonas aeruginosa produces distinctive blue-green pigments (pyocyanin) on cetrimide agar.
  4. This agar can also show fluorescent pigment production under UV light due to the presence of pyoverdine.
  5. Cetrimide agar is often used in diagnosing skin infections, particularly burn wounds and eye infections caused by Pseudomonas aeruginosa.

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