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.

A case of endocarditis caused by the yeastPichia fabianiiwith biofilm production and developedin vitroresistance to azoles in the course of antifungal treatment

“…2b). Carbon assimilation profiles were performed using the ID 32C kit (bioMérieux), with the same biocode 4275350111 always generated after 72 h at 308C [6]. Using the APILAB Plus software (bioMérieux), the isolates were identified as Candida pelliculosa (Pichia anomala) (%id 057.3; T 00.85) with an inability to assimilate erythritol as the only discrepant test result.…”

Discrimination of Candida species by paper spray mass spectrometry

“…There are more than 20 known Candida species, each with different antibiotic susceptibility profiles [1,[15][16][17]1,20,22,23]; therefore, effective treatment depends on the pathogen [14,18,20]. Hence a simple, rapid, cost-effective, and accurate method that allows for species discrimination is needed [24].…”

“…Yeasts, such as Candida, can be characterized using morphological, physiological, and biochemical criteria [24][25][26][27], but these are generally time consuming and often yield ambiguous results [1,2,12,[28][29][30]. Newer methods used to quickly speciate Candida take advantage of species-specific enzymatic characteristics [27,31,32].…”

Development of a novel, simple and rapid molecular identification system for clinicalCandidaspecies

“…All systems failed to identify Candida norvegensis, C. catenulata, C. haemulonii and C. dubliniensis. In addition, these systems require at least 3 days incubation to obtain the necessary result [2]. Molecular approaches seem to be more promising than such phenotypic methods for the rapid and accurate identification of pathogenic organisms [9].…”

“…Although these systems enable the identification of the most frequently isolated species they are time-consuming, and often not sensitive enough. They can fail to distinguish non-C. albicans species [2]. Numerous studies have evaluated and compared these systems [3 Á/7].…”