Candida guilliermondii and Other Species of Candida Misidentified as Candida famata: Assessment by Vitek 2, DNA Sequencing Analysis, and Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry in Two Global Antifungal Surveillance Programs

Candida famata (teleomorphDebaryomyces hansenii ) has been described as a medically relevant yeast, and this species has been included in many commercial identification systems that are currently used in clinical laboratories. Among 53 strains collected during the SENTRY and ARTEMIS surveillance programs and previously identified asC. famata (includes all submitted strains with this identification) by a variety of commercial methods (Vitek, MicroScan, API, and AuxaColor), DNA sequencing methods demonstrated that 19 strains wereC. guilliermondii , 14 wereC. parapsilosis , 5 wereC. lusitaniae , 4 wereC. albicans , and 3 wereC. tropicalis , and five isolates belonged to otherCandida species (twoC. fermentati and one eachC. intermedia ,C. pelliculosa , andPichia fabianni ). Additionally, three misidentifiedC. famata strains were correctly identified asKodomaea ohmeri ,Debaryomyces nepalensis , andDebaryomyces fabryi using intergenic transcribed spacer (ITS) and/or intergenic spacer (IGS) sequencing. The Vitek 2 system identified three isolates with high confidence to beC. famata and another 15 with low confidence betweenC. famata andC. guilliermondii orC. parapsilosis , displaying only 56.6% agreement with DNA sequencing results. Matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) results displayed 81.1% agreement with DNA sequencing. One strain each ofC. metapsilosis ,C. fermentati , andC. intermedia demonstrated a low score for identification (<2.0) in the MALDI Biotyper.K. ohmeri ,D. nepalensis , andD. fabryi identified by DNA sequencing in this study were not in the current database for the MALDI Biotyper. These results suggest that the occurrence ofC. famata in fungal infections is much lower than previously appreciated and that commercial systems do not produce accurate identifications except for the newly introduced MALDI-TOF instruments.