Multilocus sequence typing of strains from the Cryptococcus gattii species complex from different continents
Virginie Bellet1, Frédéric Roger1, Donika Krasteva1
1UMI 233 IRD-UM INSERM U1175 TransVIHMI, Infections mycosiques et parasitaires liées au VIH, Laboratoire de Parasitologie et de Mycologie Médicale, UFR Pharmacie, Montpellier, France.
Mycoses
|November 2, 2021
Summary
Cryptococcus gattii causes deadly meningitis. This study reveals significant genetic diversity and new sequence types among C. gattii strains, highlighting variations in antifungal resistance.
Area of Science:
- Medical Mycology
- Molecular Biology
- Infectious Diseases
Background:
- Cryptococcus neoformans and Cryptococcus gattii species complexes are major causes of cryptococcal meningitis.
- This fungal infection results in over 180,000 deaths annually worldwide.
- Effective treatment is crucial to combat this life-threatening condition.
Purpose of the Study:
- To investigate the molecular diversity of Cryptococcus gattii isolates.
- To analyze strains collected globally from 1995 to the present.
- To understand the genetic variations within C. gattii species complexes.
Main Methods:
- Multilocus Sequence Typing (MLST) was employed to assess molecular diversity.
- Antifungal susceptibility was determined using the broth microdilution method (CLSI M27-A4 protocol).
- A total of 26 clinical and environmental C. gattii strains were analyzed.
Main Results:
- Genotyping revealed serotype B strains (65.4%) predominantly in VGI, VGII, and VGVI genotypes.
- Serotype C strains (34.6%) were found in VGIII and VGIV genotypes.
- Seventeen MLST subtypes were identified, including four novel genotypes (ST553-556).
- Most isolates showed wild-type Minimum Inhibitory Concentrations (MICs) for fluconazole and flucytosine.
- Five VGI strains exhibited non-wild-type MICs for amphotericin B.
Conclusions:
- The study demonstrates considerable genetic diversity within the Cryptococcus gattii complex.
- New sequence types (STs) were identified, expanding the known genetic landscape of C. gattii.
- Understanding this diversity is crucial for tracking and managing cryptococcal meningitis outbreaks.
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