Avaliação da prevalência, fatores de virulência, susceptibilidade antifúngica e relacionamento genético de isolados clínicos e ambientais de Cryptococcus spp. e gêneros relacionados

Abstract

Cryptococcus is a genus of encapsulated yeasts belonging to the phylum Basidiomicota, which includes several species distributed around the world in different environments such as bird droppings, soil, decaying vegetation and tree hollows. Species of the Cryptococcus gattii/Cryptococcus neoformans complex are the main etiological agents of cryptococcosis, an infectious disease of worldwide distribution. Several virulence factors have been characterized for C. neoformans, such as the polysaccharide capsule, the ability to grow at 37ºC, melanin secretion, enzyme production and biofilm formation. The aim of this study was to investigate the pathogenic potential and antifungal susceptibility of Cryptococcus spp. and related genera isolated from environmental and clinical samples. Papiliotrema laurentii showed phenotypic properties more similar to the strains of the C. gattii/C. neoformans species complex. Naganishia spp. produced higher levels of phospholipase and hemolysins. However, strains of the C. gattiii/C. neoformans complex had significantly thicker capsules, produced more biofilm biomass and melanin. In addition, a greater number of strains of non-C. gattiii/C. neoformans complex revealed non-wild phenotypes to Fluconazole, Itraconazole or Amphotericin B. C. deuterogattii strains produced statistically significant more biofilm biomass than C. neoformans. Clinical isolates of P. laurentii and Nagasnishia spp. showed strong melanin production. These findings may be relevant for environmental and patient colonization in future infections, mainly because the environmental isolates have been obtained from the outside area of an important tertiary hospital in the city of Natal, RN, Brazil.