Evaluation the efficacy of some culture media in melanin production by Cryptococcus neoformans

Abstract

Abstract Cryptococcus neoformans is a capsule containing yeast pathogen, commonly found in urban environments that causes Cryptococcosis which is a worldwide fungal disease. The current study. This study was aimed to compare the ability of some culture media to detect melanin production by C. neoformans isolates. A total of 202 clinical samples obtained from patients suffering from meningitis, during the period from September 2020 through April 2021. The isolation and identification results revealed that 179 (88.61%) samples were positive for yeast growth. 29 (14.35%). Twenty-nine from 202 of samples were C. neoformans according to the morphological characteristics and the biochemical tests, and 150 (74.25%) samples for Candida spp. All C. neoformans isolates produced blue dry colonies on cryptococcus differential agar. Several differential media were used for the purpose of testing the ability of C. neoformans to produce melanin pigment, these includes: Niger seed agar medium (Staib’s Agar), and the colonies of C. neoformans appeared on this medium in a brown color after 2–5 days of incubation, Tobacco agar where those colonies gave a dark brown color after 48–72 h, and Methyldopa agar which was the best medium for the detection of melanin production because the results were faster from the other media, interestingly the colonies can produce the pigment and can growth very fast within 24hr.