Evaluation of novel culture media prepared from plant substrates for isolation and identifi cation of Cryptococcus neoformans species complex

Background: Melanin production due to phenoloxidase activity is a distinctive property of Cryptococcus neoformans and Cryptococcus gattii species complex yeasts. Therefore, an agar medium containing a precursor of melanin pigment is potentially useful to identify and differentiate cryptococcal colonies from other yeasts. Background: This study aimed to evaluate and compare the ability of Cryptococcus neoformans species complex isolates to produce brown-pigmented colonies when grown on media prepared from various plant leaves or seeds extracts. Material and Methods: Forty-six C. neoformans species complex isolates which were obtained from various environmental and clinical samples were inoculated on different media containing coriander, cumin, soybean, lupine, flax, pumpkin, basil, peppermint, and marjoram, were observed for the rate of growth and pigment production during a five-day period. Results: All isolates were pigmented on all media within 24-48 hours, and brown or dark brown colonies were observed in less than five days, while C. albicans grew but did not produce any pigment. Conclusion: The differential media tested in the present study are simple and inexpensive, and represent alternative valid tools for presumptive identification of C. neoformans species complex from clinical and environmental samples.