Evaluation of the Auxacolor System for Biochemical Identification of Medically Important Yeasts

Abstract

We compared the Auxacolor yeast identification system (Sanofi Diagnostics Pasteur) with the API 20C Aux (bioMerieux-Vitek) using 105 isolates of medically important yeasts. The Auxacolor system provided more rapid, accurate results and displayed less interobserver variability than the API 20C Aux.

Identification of Candida species in the clinical laboratory: a review of conventional, commercial, and molecular techniques

“…Campbell et al (1999) and Romney et al (2000) observed that the Auxacolor system correctly identified 94% and 91.2% of the isolates within 48 h after inoculation, respectively. These findings agree with those of Sheppard et al (1998), who found an overall correct identification rate of 91.4%, although other studies (Buchaille et al, 1998;Verweij et al, 1999) reported lower sensitivity of 80-86%. An advantage of the kit is that the isolates are not only identified by biochemical characteristics, but also that morphological features, such as the ability to form mycelia are taken into account, reducing the needs for additional tests (Verweij et al, 1999).…”

“…Auxacolor system-The Auxacolor system (Sanofi Diagnostics Pasteur, Paris, France) initially contained a database for 26 yeasts and consists of a disposable plastic microplate containing 16 wells. The first well is a negative control, while 13 wells perform colorimetric biochemical tests for conventional carbohydrate assimilation, another is for actidione resistance, and the last well is for phenoloxidade activity (Sheppard et al, 1998;Campbell et al, 1999;Romney et al, 2000). The microplates are read after 24-72 h of incubation at 30°C, and growth is visualized by color change of a pH indicator (Verweij et al, 1999).…”

“…An advantage of the kit is that the isolates are not only identified by biochemical characteristics, but also that morphological features, such as the ability to form mycelia are taken into account, reducing the needs for additional tests (Verweij et al, 1999). Of the Candida species, the Auxacolor system is capable of identifying C. albicans, C. glabrata, C. guilliermondii, C. krusei, C. lusitaniae, C. parapsilosis, C. tropicalis (Sheppard et al, 1998;Campbell et al, 1999;Romney et al, 2000), C. kefyr, C. zelanoydes (Romney et al, 2000), C. lipolytica (Sheppard et al, 1998;Romney et al, 2000), and C. inconspicua (Sheppard et al, 1998).…”

Simple Strategy for Direct Identification of Medically Important Yeast Species from Positive Blood Culture Vials

“…While the germ tube test provides rapid identification of C. albicans, non-C. albicans isolates from blood cultures are most commonly identified by commercial micromethod systems such as the API 20C AUX (API20C) (Biomerieux-Vitek) (9). This requires 24 h to obtain sufficient growth upon subculturing before inoculation and then another 48 to 72 h to identify the majority of isolates (6,9). Direct inoculation of an identification system from positive blood culture vials could reduce this delay by obviating the need for subculturing.…”

“…The Auxacolor (AUX) system (Sanofi Diagnostics Pasteur) is an identification kit that is more rapid and accurate than the API20C when used to identify common yeast species from solid media (1,6). This system is chromogenic, not turbidometric, and is little affected by changes in inoculum.…”