Comparison between uncommon yeast species (UYS)- and Candida albicans-related fungaemia can uncover specific predisposing factors with potential impact on treatment strategies.

Clinical data (including follow-up) and isolates responsible for fungaemia were collected prospectively from 27 hospitals (Paris, France ; 01/10/2002-31/12/2014). Univariate and multivariate analyses were performed to compare UYS with C. albicans fungaemia.

We analysed 339 episodes of UYS fungaemia. Of the 35 different UYS (27 ascomycetes, 8 basidiomycetes), 11 had caspofungin MIC50 >=0.5mg/L (CAS-R), and 15 had fluconazole MIC50 >=8mg/L (FCZ-R, EUCAST method). The incidence of UYS fungaemia was stable over time. When comparing with 1997 single episodes of C. albicans fungaemia, haematological malignancies (OR=2.42[1.82–3.22]) and prior exposure to antifungal drugs (OR=1.86[1.29–2.67]) were independent predisposing factors for UYS upon multivariate analysis. However, when considering the species/genera level, only infections due to species related to C. kefyr (OR=3.95[2.40–6.53]) and to Trichosporon spp. (OR=5.42[1.73–16.96]) remained associated with haematological malignancies, those due to Geotrichum spp. with acute leukaemia (OR=52.61[17.64–156.88]), and the later two with prior exposure to caspofungin (OR=15.6[3.6–67.4] and OR=12.0[3.2–45.3], respectively) but not to fluconazole. The global mortality at day 30 of the CAS-R and FCZ-R species was not different compared with C. albicans, (40%, 40%, and 35% respectively), but very divergent results were observed according to the species.

UYS encompass a huge diversity of species, each with its own behaviour and predisposing factors. This underlines the need for rapid identification of isolate at the species level in order to optimize antifungal treatment.