Sabouraud Dextrose Agar (SDA)- Composition, Principle, Preparation, Results, Uses


Sabouraud Dextrose Agar (SDA) is a type of culture medium that is widely used in microbiology for the isolation and identification of various fungi and yeasts. It was first developed by Raymond Sabouraud in 1892 as a modification of the original potato dextrose agar. SDA consists of peptones, dextrose, agar and water, and sometimes antibiotics to suppress the growth of bacteria. SDA has a low pH of around 5.6, which favors the growth of most fungi and inhibits many bacteria. SDA is commonly used to culture dermatophytes, which are fungi that cause skin infections, as well as other pathogenic or opportunistic fungi that may be present in clinical specimens, food, cosmetics or environmental samples. SDA can also support the growth of some aciduric bacteria, such as lactobacilli and propionibacteria, which may be of interest in certain applications. SDA is usually prepared as plates or slants and incubated at 25°C to 30°C for several days to allow the growth of fungal colonies. The colonies can then be observed for their morphology, color, texture and other characteristics that can help in their identification. Some fungi may also produce characteristic pigments or metabolites that can be detected by chemical tests or microscopy. SDA is a simple, inexpensive and versatile medium that has been widely used for over a century in fungal microbiology. It is still one of the most popular media for the isolation and identification of fungi and yeasts in various fields and settings.