Identification of Candida dubliniensis in a prospective study of patients in the United States

Although Candida albicans remains the fungal species most frequently isolat ed as an opportunistic oral pathogen, other yeast species are often identif ied in human immunodeficiency virus (HIV)-seropositive patients. Candida du bliniensis phenotypically resembles C. albicans in many respects, yet it ca n be identified and differentiated as a unique Candida species by its pheno typic and genetic profiles. The purpose of the present study was to prospec tively test for the presence of C. dubliniensis among clinical isolates and to determine the clinical and demographic characteristics of patients harb oring C. dubliniensis. Over a 90-day period, isolates from 724 patients tha t were presumptively identified as C. albicans were screened for C. dublini ensis by use of tests for germ tube and chlamydospore production, by detect ion of an inability to grow at 45 degrees C, by colony color on CHROMagar C andida medium, and by the results of a sugar assimilation test with the API 20C AUX yeast identification system. Among 699 isolates retrieved from tho se specimens evaluated, 5 from 25 HIV-seropositive patients and 1 isolate f rom a patient whose HIV status was unknown were shown to be consistent by p henotyping and by electrophoretic karyotyping with the European reference s train of C. dubliniensis. One of the C. dubliniensis isolates had dose-depe ndent susceptibility to fluconazole (MIC, 16 mu g/ml). These results confir m the presence of this interesting species in the United States and support the need for further investigations into the prevalence and pathogenesis o f C. dubliniensis.