Uncommon opportunistic yeast bloodstream infections from Qatar

Area of Science:

• Medical Mycology
• Infectious Diseases
• Clinical Microbiology

Background:

• Fungemia, bloodstream infections caused by fungi, poses a significant health risk, particularly in vulnerable populations.
• Uncommon yeast species are increasingly recognized as important pathogens, often associated with high mortality rates.
• Limited data exists on the prevalence and antifungal susceptibility of uncommon yeasts in the Middle East, specifically Qatar.

Purpose of the Study:

• To identify and characterize uncommon yeast species isolated from pediatric and elderly patients with fungemia in Qatar.
• To evaluate the in vitro antifungal susceptibility of these isolates to commonly used antifungal agents.
• To provide insights into the epidemiology and management of fungemia caused by rare yeasts.

Main Methods:

• Retrospective analysis of fungemia cases over a 6-year period (2004-2010).
• Isolation and identification of yeast species using Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight Mass Spectrometry (MALDI-TOF MS) and molecular methods.
• Antifungal susceptibility testing to determine minimal inhibitory concentrations (MICs).

Main Results:

• Eleven uncommon yeast species were identified from 201 episodes of fungemia in 187 patients.
• Kluyveromyces marxianus, Lodderomyces elongisporus, and Lindnera fabianii were among the identified species.
• Low minimal inhibitory concentrations were observed for isavuconazole and voriconazole against all tested uncommon yeast species.
• Antifungal drug resistance was generally low and confined to a few species.

Conclusions:

• Uncommon yeast species represent a notable cause of fungemia in Qatar, affecting both pediatric and elderly patients.
• MALDI-TOF MS is a reliable method for identifying these challenging yeast isolates.
• Isavuconazole and voriconazole show promising in vitro activity against a broad range of uncommon yeasts, suggesting potential therapeutic options.