Epidemiology, Significance and Clinical Outcomes of Bloodstream Infections Caused by Non-Candida and Non-Cryptococcus Yeasts.

INTRODUCTION

Fungaemia due to non-Candida and non-Cryptococcus yeasts is uncommon but clinically significant, particularly in immunocompromised hosts. We aimed to describe the epidemiology, microbiology and outcomes of bloodstream infections (BSIs) caused by these organisms.

METHODS

We identified all BSIs due to non-Candida and non-Cryptococcus yeasts over a 20-year period using statewide laboratory and administrative health databases.

RESULTS

Seventy-five unique episodes were identified. The most frequent genera were Trichosporon (n = 31, 41.3%), Rhodotorula (n = 26 34.7%) and Saccharomyces (n = 10, 13.3%) species. Antifungal susceptibility testing performed in 33 (44%) episodes revealed high MICs (> 16 mg/L) to echinocandins for Trichosporon and Rhodotorula species. Fluconazole MICs were universally elevated ( ≥ $$ \ge $$  32 mg/L) in Rhodotorula spp. but lower in Saccharomyces cerevisiae (2-4 mg/L). Voriconazole and posaconazole had good in vitro activity across all genera where tested. Thirty-day mortality was 22.7%, with the highest rate observed in S. cerevisiae (50.0%). Mortality was associated with malignancy (aHR 4.71, 95% CI 1.00-22.25), heart failure (aHR 11.31, 95% CI 1.66-77.14) and intensive care unit (ICU) admission (aHR 7.05, 95% CI 0.99-50.36). The presence of a central line may be protective (aHR 0.17, 95% CI 0.03-1.04). Rhodotorula infection was associated with lower mortality on univariable analysis (HR 0.11, 95% CI 0.14-0.86) compared with Trichosporon species.

CONCLUSION

Although rare, fungaemia due to non-Candida and non-Cryptococcus yeasts is associated with significant mortality and antifungal resistance. Species identification and susceptibility testing are crucial to guide treatment. Increased awareness is essential in high-risk patients, particularly those with malignancy, heart failure, or requiring ICU admission.