Aspergilli are hyaline moulds that commonly cause opportunistic infections in humans. Allergic bronchopulmonary disease is a manifestation of hypersensitivity to fungal spores or products, a common manifestation of Aspergillus species (particularly A. flavus). Aspergillus Differentiation Medium Base formulated by Pitt et al is a modification of the medium formulated by Bothast and Fennel. Aspergillus flavus develops intense yellow orange colour at the base of the colonies, which is a differential characteristic of this species. This pigmentation helps in differentiating A. flavus from other Aspergillus species. Assante et al showed that the orange yellow coloration was due to the reaction of ferric ions (from ferric ammonium citrate) with aspergillic acid or neoaspergillic acid forming a colored complex.
A mixture of chloramphenicol and dicholoran restricts the spreading of molds. It also inhibits bacterial growth and helps in the identification of fungi. Peptic digest of animal tissue and yeast extract serve as sources of nitrogen, amino acids and B complex vitamins. Ferric ammonium citrate aids in the production of yellow orange pigment characteristic of A. flavus. A. parasiticus, associated with aspergillosis also produces a yellow orange pigment similar to the one produced by A. flavus.
Storage and Shelf-life:
Store below 30°C in tightly closed container and the prepared medium at 2 - 8°C. Use before expiry date on label.