Candida nivariensis in comparison to different phenotypes of Candida glabrata.

Abstract

The purpose of the study was to establish the prevalence of new Candida glabrata complex species: Candida nivariensis and Candida bracarensis isolated from clinical material, evaluate their phenotypes and the prevalence of gene family encoding extracellular glycosylphosphatidylinositol-linked aspartyl proteases, crucial for C. glabrata virulence. Study material included 224 C. glabrata clinical strains. Candida glabrata phenotypes were identified using CHROMagar Candida medium. Strains were analysed by using C. glabrata-specific PCR for the internal transcribed spacer region to confirmed the identification. To identify C. nivariensis and C. bracarensis strains, the D1/D2 region of 26S rRNA was sequenced. The prevalence of YPS-family proteases genes was detected using standard PCR method. Candida nivariensis amounted about 6% among the total number of C. glabrata strains. Candida nivariensis strains had a white phenotype on chromogenic agar media and assimilated two sugars - trehalose and glucose. Among the 13 C. nivariensis strains, 10 did not present any YPS-family protease genes. Coexistence of all detected YPS-family protease genes was specific for C. glabrata species. This study identified C. nivariensis strains; however, no C. bracarensis strains were identified. The white phenotype of C. nivariensis was confirmed. Most strains of the new species do not present any of the tested YPS genes.