Abstract

GOMES, Fabíola Silveira; SARMENTO, Dayse Nogueira; SANTO, Elaine Patrícia Tavares do Espírito  and  SILVA, Silvia Helena Marques da. Chemotype determination and phenotypic characterization of isolated Cryptococcus from Belém, Pará State, Brazil. Rev Pan-Amaz Saude [online]. 2010, vol.1, n.4, pp.43-49. ISSN 2176-6215.  http://dx.doi.org/10.5123/S2176-62232010000400007.

Cryptococcosis is an opportunistic fungal infection that is caused by yeasts of the genus Cryptococcus, mainly Cryptococcus neoformans and Cryptococcus gattii. Due to their tropism for the central nervous system, the main clinical manifestation of the disease is cryptococcal meningitis, which most severely affects individuals with acquired immunodeficiency syndrome. There is increasing interest in some of the phenotypic aspects of these yeasts, such as capsule diameter, urea hydrolysis, and phenoloxidase activity, because they determine the virulence of the fungus. The objective of this study was to determine the chemotype of the Cryptococcus species that were recovered from 15 cases of cryptococcal meningitis and to characterize their phenotypic features. A group of yeasts that were previously identified as C. neoformans (n = 15) by the semi-automated system API ID 32C and stored in the fungal collection of the Laboratory of Mycology of the Bacteriology and Micology Section on the Instituto Evandro Chagas were chemotyped in canavanine glycine bromothymol blue medium and assessed for their growth at 37^o C, cycloheximide sensitivity, urea hydrolysis ability, and phenoloxidase activity. Based on culture in canavanine glycine bromothymol blue medium, we observed that 47% (7/15) of the yeasts were C. gattii and that 53% (8/15) were C. neoformans. Only one isolate (1/15) was able to grow at 37^o C; all isolates were sensitive to cycloheximide and could hydrolyze urea. Phenoloxidase activity was observed in all groups, occurring up to 72 h after incubation. In this study, cryptococcal meningitis cases in Belém, Pará State, Brazil, were more commonly caused by C. neoformans. Both C. neoformans and C. gattii exhibited typical phenotypic traits, and it was assumed that, virulent isolates occur in our region.

Keywords : Cryptococcus neoformans; Cryptococcus gattii; Meningitis; Cryptococcal; Phenotyping.

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