New microsatellite multiplex PCR for Candida albicans strain typing reveals microevolutionary changes

Area of Science:

• Medical Mycology
• Molecular Biology
• Genetics

Background:

• Candida albicans is a common human pathogen.
• Accurate strain differentiation is crucial for epidemiological studies and treatment strategies.

Purpose of the Study:

• To describe and characterize new microsatellite loci for molecular identification and genetic differentiation of Candida albicans.
• To evaluate the discriminatory power of these markers using a multiplex PCR strategy.

Main Methods:

• Development and characterization of five new microsatellite loci.
• Typing of 72 unrelated clinical isolates to assess polymorphism.
• Application of a multiplex PCR strategy combining three microsatellites for strain typing.
• Analysis of 114 C. albicans strains, including multiple isolates from the same patient.

Main Results:

• All five microsatellite loci were polymorphic, with 5–30 alleles and 8–46 genotypes per locus.
• A multiplex PCR strategy using three microsatellites achieved a discriminatory power of 0.99.
• Three scenarios of strain relatedness were identified: identical strains, microevolving strains, and distinct strains.
• Microevolutionary changes, including loss of heterozygosity (LOH), were observed in recurrent infections, potentially linked to fluconazole exposure.

Conclusions:

• Multiplex PCR using microsatellite markers is a highly efficient tool for rapid and accurate differentiation of C. albicans strains.
• This approach can identify fine microevolutionary events, offering insights into strain adaptation to environmental stress and treatment.