Evaluation of six commercial systems for identification of medically important yeasts

Abstract

Six commercially available systems for the identification of yeasts were evaluated using 133 clinical isolates and four reference strains that had been previously identified by conventional methods and 19 recent clinical isolates that had been identified by the ID32C system (bioMérieux, France). The total identification rates (TIR) established for the total number of strains tested and the database identification rates (DBIR) established for the strains included in the respective manufacturer databases were both determined. After incubation for 4 h, the TIR and DBIR were 78% and 84%, respectively, for the RapID Yeast Plus system (Innovative Diagnostic Systems, USA). After incubation for 24 h, the TIR and DBIR were 32% and 32%, respectively, for the ID32C, 65% and 67% for the Auxacolor system (Sanofi Diagnostics Pasteur, France), 62% and 65% for the Fungichrom I system (International Microbio, France), 52% and 65% for the Fungifast I twin system (International Microbio), and 62% and 68% for the API Candida system (bioMérieux). The maximum TIR and DBIR (+/- 1%) obtained after incubation for 48 h were 86% and 88% for the Auxacolor, 85% and 89% for the Fungichrom I, 78% and 98% for the Fungifast I twin, and 82% and 91% for the API Candida. For the ID32C, the maximum TIR and DBIR were 98% and 98%, respectively, but these values were obtained only after 72 h of incubation. In addition, the six systems varied in their ease of use and readings. In conclusion, based on results obtained with 156 strains, the Auxacolor and Fungichrom systems seem the most appropriate for use in a clinical microbiology laboratory, due to their ease of use and reading, their rapidity, their cost per test, and their relatively high TIR results, which indicated acceptable performance with strains frequently isolated in our hospital. For a reference identification, the ID32C remains the sole system usable.

Are the Conventional Commercial Yeast Identification Methods Still Helpful in the Era of New Clinical Microbiology Diagnostics? A Meta-Analysis of Their Accuracy

“…The main characteristics of the 26 studies (32-57), which were published between 1993 and 2014, are shown in Table 1 (see also Table S2 in the supplemental material). Among the 26 studies, 12 (32-34, 36-38, 40-43, 45, 54) reported on the identification performance of the AuxaColor system, 5 (35,38,39,43,54) reported on the identification performance of the API ID32C system, and 13 (44,(46)(47)(48)(49)(50)(51)(52)(53)(54)(55)(56)(57) reported on the identification performance of the Vitek 2 system operating with the ID-YST (fluorimetric) card (44,(46)(47)(48)(49) and/or the YST (colorimetric) card (47,48,(50)(51)(52)(53)(54)(55)(56)(57); among them, three were direct-comparison studies, of which two were between the AuxaColor and API ID32C systems (38,43) and one was among the AuxaColor, API ID32C, and Vitek 2 systems (54). Two studies evaluating the Vitek 2 system compared the colorimetric YST card with the older fluorimetric ID-YST card (47,48); however, we decided to include the results of these studies only with respect to the YST card.…”

Experience with the MicroSeq D2 Large-Subunit Ribosomal DNA Sequencing Kit for Identification of Commonly Encountered, Clinically Important Yeast Species

“…The commercially available yeast identification methods (1,2,4,5,9,(13)(14)(15)17) have easily identified the common yeast species; however, uncommon and newly described species present a significant challenge. Phenotypic characteristics often cannot distinguish between species that have overlapping phenotypic characters.…”

Rapid Identification of Candida glabrata with a New Commercial Test, GLABRATA RTT

“…These results match those achieved with slower trehalase-based tests (4,12,19). Widely used commercial yeast identification systems such as API20CAUX, Auxacolor, Fungichrom, and Vitek YBC often perform less well than GLABRATA RTT (2,8).…”