The role of Candida dubliniensis in oral candidiasis in human immunodeficiency virus-infected individuals

There is an increasing interest in non-albicans Candida species because of the increasing number of fungal infections they cause. Most of these infections can be found in immunocompromised individuals, especially in those infected with human immunodeficiency virus (HIV). Candida dubliniensis is a recently identified yeast, mostly isolated in HIV-positive individuals with oral candidiasis. Candida dubliniensis is a germ tube- and chlamydospore-form yeast. Thus, it shares diagnostic characteristics with Candida albicans. Probably, Candida dubliniensis has been present in the community for a long time and has been misidentified as Candida albicans. Significant phenotypic characteristics of Candida dubliniensis (difference in the carbohydrate assimilation profile, difference in colony color on CHROMagar Candida, and positive tetrazolium test, etc.) have been found, but none of them seem to be sufficient alone for the definitive identification of the species. Recently, PCR tests were developed to discriminate Candida albicans from Candida dubliniensis. However, these prove difficult in the context of routine mycological diagnostics. Moreover, an increased resistance to antifungal drugs has been described. This shows the importance of identification of Candida dubliniensis. To elucidate the current insight into Candida dubliniensis, the phenotypic and genotypic characteristics as well as the prevalence and the antifungal drug susceptibilities of this species are discussed from a clinical standpoint.