Candida dubliniensis identification in Brazilian yeast stock collection

We investigated the presence of Candida dubliniensis among isolates previously identified as Candida albicans and maintained in a yeast stock collection from 1994 to 2000. All isolates were serotyped and further evaluated for antifungal susceptibility profile. After doing a screening test for C. dubliniensis isolates based on the capability of colonies to grow at 42°C, its final identification was obtained by randomly amplified polymorphic DNA (RAPD) analysis using three different primers. A total of 46 out of 548 screened isolates did not exhibit growth at 42°C and were further genotyped by RAPD. Eleven isolates were identified as C. dubliniensis with RAPD analysis. Regarding serotypes, 81.5% of C. albicans and all C. dubliniensis isolates belonged to serotype A. Of note, 9 out of 11 C. dubliniensis isolates were obtained from patients with acquired immunodeficiency syndrome (Aids) and all of them were susceptible to azoles and amphotericin B. We found 17 (3%) C. albicans isolates that were dose-dependent susceptibility or resistant to azoles. In conclusion, we found a low rate of C. dubliniensis isolates among stock cultures of yeasts previously identified as C. albicans. Most of these isolates were recovered from oral samples of Aids patients and exhibited high susceptibility to amphotericin B and azoles. C. albicans serotype A susceptible to all antifungal drugs is the major phenotype found in our stock culture.