Candida nivariensis: identification strategy in mycological laboratories

Candida nivariensis is a cryptic fungal species classified within the Candida glabrata complex. It was described for the first time in 2005 by the means of DNA sequencing. We report a rare case of C. nivariensis deep-seated infection occurring in a 77-year-old man hospitalized for cysto-prostatectomy. Phenotypic testing based on the direct examination and the macroscopic features of the in vitro culture initially suggested C. glabrata species, while MALDI-TOF mass spectrometry enables correct identification. The isolate was found resistant to fluconazole, like in almost 20% of the reported cases. Herein, we present our practical strategy to reliably characterize this rare cryptic species. To date, MALDI-TOF mass spectrometry-based analysis showed very good results for such a purpose.