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Published on: February 14, 2018
Antifungal Susceptibilities of Rare Yeast Isolates
Deniz Turan1, Zafer Habip2, Hakan Odabaşı3
1Istanbul Provincial Health Directorate ISLAB-2 Central Laboratory, Prof. Dr. Süleyman Yalçın City Hospital, Kadıköy, 34722 Istanbul, Türkiye.
Abstract:
The recent increase in the number of rare yeasts isolated from clinical specimens is a cause for concern, requiring accurate identification of these yeasts and assessment of their antifungal susceptibility to guide treatment. In this regard, we identified 196 rare yeasts isolated from various clinical specimens, mostly urine and respiratory tract specimens of patients hospitalized in intensive care unit and wards, using MALDI-TOF MS, and assessed their susceptibility to amphotericin B, fluconazole, voriconazole, posaconazole, itraconazole, isavuconazole and anidulafungin using the EUCAST broth microdilution method. Among the rare yeast species we isolated, Candida lusitaniae (13.8%) was the most common, followed by Magnusiomyces capitatus (13.3%), Candida fabianii (12.2%), and Trichosporon asahii (11.7%). Antifungal susceptibility testing revealed high echinocandin MIC values against Magnusiomyces spp., Trichosporon spp., and Rhodotorula mucilaginosa isolates. Similarly, we found high MIC values for fluconazole against the isolates of Magnusiomyces spp., T. asahii, R. mucilaginosa, and several Candida spp., including Candida guilliermondii, Candida pararugosa, Candida rugosa, Candida pelliculosa, Candida norvegensis, and Candida fabianii. We found similar MIC values across phylogenetically closely related species. In conclusion, prompt identification of rare yeasts and assessment of their antifungal susceptibilities are essential for effective treatment of the infections they cause.
Insights
The rise in rare yeast infections necessitates precise identification and antifungal susceptibility testing. This study identified 196 rare yeasts, revealing common species and highlighting resistance patterns to guide clinical treatment.
Area of Science:
- Medical Mycology
- Clinical Microbiology
- Infectious Diseases
Background:
- Increasing isolation of rare yeasts from clinical samples poses a diagnostic challenge.
- Accurate identification and antifungal susceptibility are crucial for effective patient management.
Purpose of the Study:
- To identify rare yeasts from clinical specimens and determine their antifungal susceptibility profiles.
- To provide data guiding the treatment of rare yeast infections.
Main Methods:
- Matrix-assisted laser desorption/ionization–time of flight mass spectrometry (MALDI-TOF MS) for yeast identification.
- European Committee on Antimicrobial Susceptibility Testing (EUCAST) broth microdilution method for antifungal susceptibility testing.
- Testing against amphotericin B, fluconazole, voriconazole, posaconazole, itraconazole, isavuconazole, and anidulafungin.
Main Results:
- 196 rare yeast isolates identified, with *Candida lusitaniae*, *Magnusiomyces capitatus*, *Candida fabianii*, and *Trichosporon asahii* being most common.
- High minimum inhibitory concentration (MIC) values observed for echinocandins against *Magnusiomyces* spp., *Trichosporon* spp., and *Rhodotorula mucilaginosa*.
- High fluconazole MIC values found for *Magnusiomyces* spp., *T. asahii*, *R. mucilaginosa*, and various *Candida* species.
Conclusions:
- Accurate identification of rare yeasts is essential for clinical microbiology laboratories.
- Antifungal susceptibility testing is critical for guiding therapy against emerging rare yeast pathogens.
- Similar antifungal susceptibility patterns were noted among phylogenetically related yeast species.
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