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Published on: February 14, 2022
Drug susceptibility of 64 strains of Rhodotorula sp
Paweł Krzyściak1, Anna B Macura
1Department of Mycology, Chair of Microbiology, Jagiellonian University Collegium Medicum, 18 Czysta Street, 31-121 Cracow, Poland. p.krzysciak@gmail.com
Abstract:
Rhodotorula sp. have emerged as opportunistic pathogens, particularly in immunocompromised patients. Knowledge about the susceptibility of Rhodotorula strains to the common antifungal drugs is essential for the treatment of such new infections. The 68 isolates identified as: Rhodotorula mucilaginosa (47 strains; 69%), R. minuta (14; 21%) and R. glutinis (7; 10%) obtained from various sources (feces, skin and nails, vagina and hospital environment) were tested for susceptibility to 5-fluorocytosine (5FC), amphotericin B (AMB), fluconazole (FLC) and itraconazole (ITR). All of the isolates had low MICs for AMB and 5FC. For ITR, the R. minuta isolates had the lowest MICs within a range 0.125-0.25 mg/l and for FLC all isolates affected within the range 2-64 mg/l. The majority of R. mucilaginosa isolates (82.2%) had MICs in the range 64-128 mg/l for FLC and 95.6% of isolates had MICs above or equal to 2 mg/1 for ITR.
Insights
Rhodotorula yeast, often found in hospitals, can cause infections in immunocompromised patients. This study found all Rhodotorula strains susceptible to common antifungals like amphotericin B and 5-fluorocytosine.
Area of Science:
- Medical Mycology
- Antimicrobial Susceptibility Testing
- Opportunistic Infections
Background:
- Rhodotorula species are increasingly recognized as opportunistic pathogens, posing risks to immunocompromised individuals.
- Understanding the antifungal susceptibility patterns of Rhodotorula is crucial for effective clinical management.
Purpose of the Study:
- To determine the in vitro susceptibility of clinical Rhodotorula isolates to common antifungal agents.
- To identify potential resistance mechanisms or variations in susceptibility among different Rhodotorula species.
Main Methods:
- Sixty-eight Rhodotorula isolates (R. mucilaginosa, R. minuta, R. glutinis) were identified from diverse clinical and environmental sources.
- Antifungal susceptibility testing was performed using standard methods to evaluate minimum inhibitory concentrations (MICs) for 5-fluorocytosine (5FC), amphotericin B (AMB), fluconazole (FLC), and itraconazole (ITR).
Main Results:
- All Rhodotorula isolates exhibited low MICs for amphotericin B and 5-fluorocytosine.
- Rhodotorula minuta isolates showed the lowest MICs for itraconazole (0.125-0.25 mg/l).
- Fluconazole MICs ranged from 2-64 mg/l for all isolates, with most R. mucilaginosa strains showing high MICs (64-128 mg/l) for fluconazole and itraconazole (≥2 mg/l).
Conclusions:
- Rhodotorula species demonstrate broad susceptibility to amphotericin B and 5-fluorocytosine.
- Fluconazole and itraconazole may be less effective against certain Rhodotorula species, particularly R. mucilaginosa, necessitating careful consideration in treatment strategies.
