key term - Sabouraud's dextrose agar

Definition

Sabouraud's dextrose agar is a type of fungal culture medium specifically designed to isolate and cultivate dermatophytes and other types of fungi. It contains peptones, dextrose, and a low pH to inhibit bacterial growth while promoting fungal growth.

5 Must Know Facts For Your Next Test

1. Sabouraud's dextrose agar has a low pH (around 5.6) which helps suppress bacterial growth.
2. This medium is particularly useful for isolating fungi from clinical specimens, including those causing respiratory infections.
3. It commonly contains antibiotics like chloramphenicol or gentamicin to further prevent bacterial contamination.
4. Sabouraud's dextrose agar can be modified with cycloheximide to inhibit the growth of saprophytic fungi, allowing for better isolation of pathogenic species.
5. Fungi such as Aspergillus and Candida are frequently isolated using this medium.

Review Questions

• Why is Sabouraud's dextrose agar formulated with a low pH?
• Which types of microorganisms are primarily cultivated using Sabouraud's dextrose agar?
• What modifications can be made to Sabouraud's dextrose agar to enhance its effectiveness in isolating pathogenic fungi?

Related terms

Dermatophytes: Fungi that cause infections in the skin, hair, and nails.

Aspergillus:

A genus of fungi known to cause respiratory infections, especially in immunocompromised individuals.

Cycloheximide: An antibiotic used to inhibit the growth of non-pathogenic fungi on culture media.