Sabouraud's Dextroe Agar

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Cultural characteristics:- Cryptococcus is an aerobe requiring a temperature of 30-35 o C for its growth. It grows on most standard fungal culture media. It does not grow ≥370C. It does not grow in the presence of Cycloheximide at concentrations used in Sabouraud’s dextrose agar (SDA). It has ability to produce melanin pigment by using various precursors of melanin in the media. I] Culture Media For primary isolation: - . For primary isolation of cryptococcus bacteriological media like blood agar, chocolate agar and Brain heart infusion agar, Cystein-heart haemoglobin agar, bird seed agar and sunflower seed agar can be used (Chander J, 2009). On Blood and brain Heart Infusion Agar-Cryptococcus grows at 370 C as buff coloured mucoid colonies. (REFERENCE) Chocolate Agar- Used for capsule demonstration. When subculture are to be done on this medium and incubated at 37oC in a candle jar with raised pCO2 mucoid colonies were obtained after 24 hours (Perfect JR and Cox GM, 2005). Colony morphology C. gattii and C. neoformans grow readily on SDA. Colonies…show more content…
neoformans. C. neoformans produce a brown-black pigment on the medium; all other yeasts produce no pigment or light yellow. Esculin is a beta-glucose-6, 7-dihydroxycoumarin. C. neoformans produce pigment because the 6,7-dihydroxycoumarin component of the esculin molecule is converted to a melanin-like pigment. Edberg SC et al thought that the reaction was similar to the conversion of diphenols, aminophenols, and diaminobenzenes to melanin. They have been studied isolates of C. neoformans, C. albidus, C. luteolus, and C. terreus and representatives of the genera Candida, Torulopsis, Geotrichum, and Rhodotorula, plus environmental field studies, demonstrated that over 95% of C. neoformans isolates were correctly identified, whereas all other fungi were

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