Phenotypic and molecular characterization of Candida nivariensis sp. nov., a possible new opportunistic fungus

Abstract

The new species Candida nivariensis, isolated from the clinical samples of three patients in Spain over a 3-year period, is presented here. This species can be easily differentiated from Candida glabrata, the closest genetic species, by different colony color on CHROMagar and by its ability to ferment trehalose. The analyses of the internal transcribed spacer region and the D1-D2 region of the 26S rRNA gene sequences support a new species designation.

FIG. 1.

Agarose gel electrophoresis of the PCR products obtained with the primers specific for C. glabrata. Lanes 1 to 3, atypical isolates (HC5937-63, HC7609-30, and HC4292-20, respectively); lanes 4 to 7, C. glabrata (HC3924-30, HC3279-29, HC1103-80, and ATCC 90030, respectively); lane 8, negative control (PCR mix without DNA template); lane M, DNA molecular size marker (100-bp ladder).

FIG. 2.

Colonies on CHROMagar Candida medium. 1, C. albicans 5039/95 blue colonies; 2, C. glabrata ATCC 90030; 3, C. glabrata 3924/30 pink colonies; 4, C. nivariensis HC4292-20 white colonies.

FIG. 3.

Neighbor-joining tree based on Kimura two-parameter corrected nucleotide distances among ITS region (A) and D1-D2 26S rRNA genes (B) of the Candida nivariensis isolates and other related species. Branch lengths are proportional to distance. Bootstrap replication frequencies (1,000 replications) are indicated on the nodes. C., Candida; K., Kluyveromyces; Sacch., Saccharomyces; Clav., Clavispora; Schz., Schizosaccharomyces; Cryp., Cryptococcus.