Use of specialised isolation media for recognition and identification of Candida dubliniensis isolates from HIV-infected patients

During a study of oral rinses of 130 HIV-infected individuals, both typical and atypicalCandida albicans colonies were isolated from ten patients on a yeast differential medium. TypicalCandida albicans colonies were light green; atypical colonies were dark green. Both types of colonies were germ tube-positive and produced chlamydospores. However, DNA fingerprinting of the atypical isolates with the Ca3Candida albicans-specific probe showed that they belonged to the recently described speciesCandida dubliniensis.Candida dubliniensis colonies could also be differentiated fromCandida albicans colonies on isolation plates by the absence of fluorescence of colonies on methyl blue-Sabouraud agar under Wood's light. Among other phenotypic characteristics, only the absence of intracellular β-glucosidase activity reliably distinguishedCandida albicans fromCandida dubliniensis.Candida dubliniensis may be underreported in clinical samples because most currently used isolation and identification methods fail to recognize this yeast.