In vitro susceptibility of clinical isolates of Saccharomyces cerevisiae

Gomez-Lopez A., Isla G., Cuesta I., Rodriguez-Tudela J.L., Cuenca-Estrella M.

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Background: The incidence of opportunistic invasive fungal infections has increased dramatically in recent years. Saccharomyces cerevisiae, a yeast used in food industry and as a probiotic, is increasingly reported as etiologic agent of human infections, and considered as a possible emerging pathogen. We have reviewed the antifungal susceptibility profile of a collection of clinical isolates of S. cerevisiae in order to give any insight on the management of this emerging infection. Methods: A total of 57 isolates received in our institution over a period of 11 years (1997 to 2007) was evaluated. The isolates were identified by routine morphological and physiological tests. MICs of amphotericin B (AMB), fluconazole (FLC), itraconazole (ITC), voriconazole (VRC) , ravuconazole (RVC), posaconazole (POS), caspofungin (CAS), micafungin (MCF) and anidulanfungin (AND) were determined according to the recommendations proposed by the European Committee on Antifungal Susceptibility Testing for fermentative yeast (EUCAST-definitive document). Results: Most of the 57 strains were isolated from vaginal exudates (15/57, 26.3%), oropharyngeal exudates (11/57, 19.3%), blood (8/57, 14.0%), and biopsy specimens (7/57, 12.3%). A slight increase in the number of S. cerevisiae strains received was detected in the last years (1.31% to 3.36% from 1997 to 2007). The majority of the strains (54/55, 98.1%) were considered susceptible in vitro to AMB (tentative MIC breakpoint MIC 4 mg/L) were detected in 35% of the strains. Whereas, elevated MICs of ITC, VRC, RVC and POS (MICs >1 mg/L) were detected in 18.5%, 7.8%, 2.4% and 5.3.% of the strains respectively. In addition, echinocandins demonstrated great activity against most of the strains. (GM for CAS, MCF and AND were respectively 0.36, 0.04 and 0.08 mg/L) Conclusions: This species seems to be an emerging pathogen and should not be dismissed as a non-pathogenic microorganism when recovered from clinical sources. AMB, new azoles and echinocandins showed good in vitro activity against this fungus.

abstract No: 

P 1307

Full conference title: 

19th European Congress of Clinical Microbiology and Infectious Diseases
    • ECCMID 19th (2009)