Introduction: In adapting VITEK2 for identification of clinical yeast isolates, we have found that some isolates were described as “Candida tropicalis / Candida parapsilosis ”. Objectives: Hence, in this study, we investigated the possible factors contributing to the ambiguous results. Methods: Clinical isolates with the ambiguous resultswere subject to sequencing analysis for identification based on their D1/D2 region of rDNA. And the results of each reaction of VITEK 2 of 82 C. parapsilosis and 256 C. tropicalis were compared to identify the possible causes. Results: VITEK 2 successfully identified 96.6% (84/87) C. parapsilosis but failed to identify 59 out of 270 (21.9%) C. tropicalis. Among those 59, 52 (88.1%) were described as C. parapsilosis / C. tropicalis. In VITEK reactions, 65 of 82 (79.3%) C. parapsilosis and 44 of 256 (17.2%) C. tropicalis were positive on the L-Arabinose reaction.However, 39 of the 52 (75%) C. tropicalis described as C. parapsilosis / C. tropicalis by VITEK 2 were positive on the L-Arabinose reaction. Conclusion: (1). One fifth of clinical C. tropicalis isolates were described as “Candida tropicalis / Candida parapsilosis” by VITEK 2. (2). L-ARABINOSE assimilation may be the key factor contributing to the failure.
Date:
2013-06
Relation:
International Journal of Antimicrobial Agents. 2013 Jun;42(Suppl. 2):S98.
