Identification and antifungal susceptibility testing of Candida haemulonii complex isolated from clinical samples

Candida haemulonii complex (Candida haemulonii [I], Candida duobushaemulonii [II], and Candida haemulonii var. vulnera [III]) has become relevant in recent times, not so much because of a high incidence in human clinical sample cultures but because of its remarkable antifungal resistance. The objective of this study was to evaluate several methods for the identification of this uncommon species of Candida. Ten isolates of C. haemulonii were identified by biochemical and proteomic methods, and their antifungal susceptibility testing was performed by both commercial and reference methods. MALDI-TOF MS (Vitek MS and Vitek MS PRIME) and Vitek2 correctly identified these genera but API method did not. There was a good correlation between the commercial methods and the reference methods for the AST. In conclusion Vitek MS, Vitek MS PRIME, and Vitek2 systems, but not API32C, are reliable for identification of C. haemulonii complex. Furthermore, MALDI-TOF MS systems could identify to the subspecies level. Commercial methods for antifungal susceptibility testing are valid for the study of this species and confirm amphotericin B and to azole resistance.