Phenotypic characterization of biofilm-forming environmental isolates of Cryptococcus neoformans and C. gattii and evaluation of the ERG11 gene obtained from the city of Araraquara.

• Grant number: 25/03994-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2025
• End date: July 31, 2026
• Field of knowledge: Health Sciences - Pharmacy
• Principal Investigator: Ana Marisa Fusco Almeida
• Grantee: Maria Júlia Siqueto
• Host Institution: Faculdade de Ciências Farmacêuticas (FCFAR). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil

Abstract

Cryptococcosis is a systemic infection caused by the encapsulated yeasts Cryptococcus neoformans, which primarily affects immunocompromised individuals, and C. gattii, which mainly impacts immunocompetent individuals. The infection typically begins with the inhalation of these yeasts or spores from their teleomorphic phase, specifically Filobasidiella neoformans and Filobasidiella bacillispora. Key virulence factors, including the polysaccharide capsule and proteolytic enzymes, allow these fungi to invade the bloodstream and reach the central nervous system, leading to meningitis, which can ultimately be fatal. The main resistance mechanisms of these fungi include efflux pumps, alterations in target enzymes, and the formation of biofilms. Cryptococcus exhibits resilience against available antifungal treatments, compounded by a dwindling supply of synthetic fungicides and challenging economic conditions, which hinder effective clinical management of the disease. Consequently, this study aims to isolate strains of C. neoformans and C. gattii and characterize them phenotypically from environmental samples taken from rural and urban areas of the municipality of Araraquara/SP, as well as verify their susceptibility profiles, ability to form biofilms and evaluate the expression of the ERG11 gene as a marker of resistance to fluconazole. (AU)