Auxacolor, a new commercial system for yeast identification: evaluation of 182 strains comparatively with ID 32C

The incidence of deep candidiasis, particularly in immunocompromised patients, and the emergence of less sensitive yeast species to new antifungal agents explain the interest of their rapid identification. A new identification system, Auxacolor (Sanofi Diagnostics Pasteur), has been evaluated, comparatively to ID 32C strip taken in reference (bioMérieux SA). These systems include respectively 13 and 29 carbohydrate assimilation tests. One hundred and sixty-nine strains belonging to 17 common yeast species isolated from biological specimens were identified. Moreover, 13 strains belonging to seven species rarely isolated and not included in the Auxacolor data base were tested. Correct biochemical profiles were obtained with 95.2% of the strains from the first panel. These profiles alone permit correct identification of 62.7% of them (n = 106). The remainders (Candida glabrata, Candida krusei, Candida guilliermondii, Candida inconspicua and Candida lipolytica) require time consuming additional morphological observations for a definitive identification. However, the time needed to obtain the biochemical profiles of these 106 strains was shorter when using Auxacolor: 77.4% of the strains were identified at 24 h with Auxacolor and 47.1% were identified at 24 h with ID 32C. Species from the second panel were not identified (seven strains) or incorrectly identified (six strains). The Auxacolor system was found to be reliable when performed in conjunction with morphological tests and easy to use for the identification of most medically important yeasts.