Candida haemulonii complex: species identification and antifungal susceptibility profiles of clinical isolates from Brazil

Received 9 June 2014; returned 8 July 2014; revised 10 July 2014; accepted 19 July 2014Objectives: The emerging fungal pathogens comprising the Candida haemulonii complex (Candida haemulonii,Candida haemulonii var. vulnera and Candida duobushaemulonii) are notable for their antifungal resistance.Twelve isolates with phenotypic similarity to C. haemulonii were recovered from patients in Brazilian hospitals.Here we aimed to identify these isolates by a molecular approach, using the current classification of this fungalcomplex, and to evaluate their antifungal susceptibility profiles.Methods: The fungal isolates were rechecked to certify their authentication by mycology methodologies andthen characterized by ITS1-5.8S-ITS2 gene sequencing. A susceptibility assay was performed using the brothmicrodilution method published by CLSI (M27-A3/M27-S3).Results: Based on biochemical tests, all Brazilian isolates were identified as C. haemulonii. After employing ITSsequencing,fiveisolateswereidentifiedasC. haemulonii,fourasC. duobushaemulonii andthreeasC. haemuloniivar. vulnera. All 12 clinical isolates were resistant to amphotericin B (MICs ranged from 2 to .16 mg/L) and flu-conazole (MICs ≥64 mg/L). One isolate of C. haemulonii var. vulnera and two isolates of C. duobushaemuloniiweresusceptible-dose dependent to itraconazole, while the remaining isolates (75%) were resistant to this anti-fungal. Eight out of 12 isolates (66.7%) were resistant to voriconazole (MICs ≥16 mg/L), while all isolates weresusceptible to caspofungin (MICs ≤0.5 mg/L).Conclusions: Our results reinforce the importance of molecular identification in differentiating species of theC. haemulonii complex. Moreover, the antifungal multiresistant profile of clinical isolates of the C. haemuloniicomplex represents a challenge to the treatment of such infections.Keywords: Candida haemulonii complex, Brazilian hospitals, resistance, antifungal susceptibility