Superficial candidosis by Candida duobushaemulonii: An emerging microorganism

The Candida haemulonii species complex and other phylogenetically related species, such as Candida auris, are emerging pathogens. The C. haemulonii complex comprises C. haemulonii, C. haemulonii var. vulnera, and Candida duobushaemulonii species. The correct identification of this fungal complex is clinically and epidemiologically relevant; however, conventional identification methods are currently inadequate. In this study, we report the molecular reidentification of two clinical isolates: isolate 553 that was recovered from a patient with total dystrophic onychomycosis and isolate 77-18 from a patient with mucocutaneous candidiasis. Both patients had diabetes mellitus as baseline disease. These isolates were initially identified as C. haemulonii by the VITEK® 2 system but were later determined to be C. duobushaemulonii based on the amplification and sequencing of a 115-bp fragment of the region of 26S rDNA. The isolates were resistant to fluconazole, and only isolate 553 was resistant to amphotericin B. Patients showed clinical and mycological cure after treatment with itraconazole. The clinical and microbiological data of these two cases of superficial candidiasis caused by C. duobushaemulonii, along with previous reports about infections with the C. haemulonii complex species, suggest that patients with diabetes mellitus are highly susceptible to infection with these fungi. Therefore, for diagnosing candidiasis in patients with diabetes mellitus, yeasts must be identified at the species level, and antifungal susceptibility testing must be carried out for adequate treatment.