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Usefulness of chromogenic agar Candida ID2 for differentiating Candida dubliniensis from Candida albicans

Abstract number: 1135_165

Eraso E., Ismail S., Villar Vidal M., Marcos C., Moragues M.D., Madariaga L., Pontón J., Quindós G.

Objective:  

To test the hypothesis that Candida dubliniensis and Candida albicans isolates can be differentiated on the basis of colony color in the chromogenic media Candida ID2 (bioMérieux, France) and CHROMagar Candida (CHROMagar, France).

Methods:  

One hundred C. dubliniensis and 100 C. albicans isolates were tested on Candida ID2 and CHROMagar Candida agar plates. Isolates had been previously identified by conventional mycological methods, as the germ tube induction test in serum, microscopical morphology and chlamydospore formation in corn meal agar with Tween 80, and carbon source assimilation with the commercial kit API ID 32C (bioMérieux). C. dubliniensis identification was confirmed by PCR with specific primers. Prior to testing, each strain was subcultured for 24–48 h at 36 ± 1°C on Sabouraud glucose agar to ensure viability. Plates were incubated at 36 ± 1°C and read for visual colony color independently by three investigators after 24 and 48 h of incubation.

Results:  

All yeast isolates grew well on both agars after 24 h of incubation, although growth on CHROMagar Candida was slower and colonies smaller. After 48h of incubation, all C. dubliniensis isolates produced blue turquoise colonies on Candida ID2, whereas 91 C. albicans isolates grew as blue cobalt colonies and 9 as blue turquoise colonies (Chi square, p < 0.01). However, on CHROMagar Candida 13 of C. albicans isolates evaluated gave a lighter shade of green and 12 gave dark green color. In contrast, 62 C. dubliniensis isolates gave dark green color. Therefore, the sensitivity and the specificity for differentiating between C. albicans and C. dubliniensis on Candida ID2 chromogenic medium were 100% and 91%, respectively.

Conclusion:  

Candida ID2 agar provides a simple laboratory tool for the differentiation of C. dubliniensis from C. albicans in clinical microbiology laboratories. This work was financed in part by the project IE019 ETORTEK-2002 (Diamolfun subproject) from the Departamento de Industria, Comercio y Turismo del Gobierno Vasco-Eusko Jaurlaritza.

Session Details

Date: 01/08/2007
Time: 00:00-00:00
Session name: XXIst ISTH Congress
Subject:
Location: Oxford, UK
Presentation type:
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