Cryptococcus neoformans var. neoformans isolated in Havana city

• Published in: Memórias do Instituto Oswaldo Cruz 1990-04, Vol.85 (2), p.245-245, Article 245
• Main Authors: Andreu, C F, Machín, G M, Bernal, L P, Morales, R R, Herrera, C A
• Format: Article
• Language: English
• Subjects: Cerebrospinal Fluid - microbiology; Cryptococcus neoformans - isolation & purification; Cuba; Culture Media; Humans
• ISSN: 0074-0276; 1678-8060; 0074-0276
• DOI: 10.1590/S0074-02761990000200019

Cryptococcosis, an opportunistic infection caused by both varieties of Cryptococcus neoformans , is one of the mycoses whose incidence has increased in the last few years, generally associated with immunosuppresive treatment and, more recently, with AIDS. Although most cases are caused by C. neoformans var. neoformans , at least two cases are known to be caused by gattii variety in AIDS patients. In 1982 K. J. Kwon-Chung et al. used a new culture medium known as CGB (canavanine-glycine-bromothymol blue) which allows to differentiate, with high specificity, C. neoformans varieties on the basis of the properties of the gattii variety, which is resistant to L-canavanine and uses glycine as unique source of carbon. By using this medium, we studied 22 strains of C. neoformans isolated from cerebrospinal fluids of patients admitted to Havana City hospitals. These strains were identified as C. neoformans by standard methods. The test was positive if the color of the medium changed from yellow-greenish (pH 5.8 to deep blue (pH > 7.0) in the first 5 days of incubation at 25-30 degree C. No color change was observed on this medium with any of the 22 studied strains, so they were identified as C. neoformans var. neoformans .