The BD Phoenix system was evaluated for species-level identification of yeasts (250 clinical isolates) and compared with the Vitek 2 system, using ribosomal internal transcribed spacer (ITS) sequence analysis as the gold standard. Considering only the species included in each system's database, 96.3% (236/245) and 91.4% (224/245) of the isolates were correctly identified by BD Phoenix and Vitek 2, respectively.
During the last decades, the growing number of vulnerable hosts such as critically ill or otherwise immunocompromised patients-e.g., individuals with advanced HIV infection or cancer who are undergoing transplant-has resulted in ever-increasing diagnoses of fungal infections (1, 2), including those caused by unusual opportunistic yeasts (3). Together with Candida albicans, the species most frequently isolated from clinical specimens (4, 5), other yeast species are increasingly recovered from patients with well-documented infections (6-8). They encompass non-albicans Candida species, including the rarer species Candida famata, Candida kefyr, Candida lipolytica, Candida rugosa, and Candida utilis, as well as uncommon species belonging to the genera Trichosporon, Rhodotorula, Pichia, Malassezia, and Saccharomyces (3).It was recently observed that some yeast species are highly virulent and show reduced susceptibility to one or several antifungal agents (2,3,(8)(9)(10)(11)(12) and that this has important clinical repercussions, often resulting in therapeutic failures (6, 13-15). Thus, accurate identification of these species is of utmost importance (16), but this goal is difficult to achieve, at least using conventional phenotypic methods (17,18). In contrast, the newly developed matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) method may offer a highly discriminatory tool for identification of yeast isolates to the species level for C. albicans and Candida glabrata with unusual phenotypic or biochemical profiles as well (17), but to date its use has been curtailed or confined to large clinical microbiology laboratories (19).In this study, the performance of the BD Phoenix Yeast ID panel for use with the Phoenix system (Becton, Dickinson Diagnostics, Sparks, MD) was compared to that of the Vitek 2 colorimetric YST card for use with the Vitek 2 system (bioMérieux, Marcy l'Etoile, France) using a large collection of clinical isolates from common and less-common yeast species.(This work was presented in part at the 23rd European Congress of Clinical Microbiology and Infectious Diseases, Berlin, Germany, 27 to 30 April 2013.)A total of 250 selected isolates, representing 29 yeast species from seven genera (see Table S1 in the supplemental material), were routinely obtained from mycological cultures of clinical specimens (i.e., blood, cerebrospinal fluid, respiratory tract, stool, and urine) of individual patients hospitalized at the Università Cattolica del Sacro Cuore of Rome (Italy) during the calendar year 2012. Isolate identification was obtained as previously describ...