Optimization and Validation of Candida auris Short Tandem Repeat Analysis.

Area of Science:

• Medical Mycology
• Infectious Diseases
• Genetics

Background:

• Candida auris is a transmissible yeast causing outbreaks, particularly in intensive care units.
• Understanding transmission routes through isolate genotyping is crucial for outbreak management.
• Previous short tandem repeat (STR) genotyping methods for C. auris existed but required further validation and optimization.

Purpose of the Study:

• To determine the discriminatory power of STR genotyping for Candida auris isolates.
• To compare the resolution of STR genotyping with whole-genome sequencing (WGS) SNP analysis.
• To optimize and validate an enhanced STR genotyping panel for C. auris.

Main Methods:

• STR analysis was performed on 171 C. auris isolates with known WGS data.
• The STR assay was optimized by adding two additional STR markers to improve clade IV separation.
• Results were compared with WGS single-nucleotide polymorphism (SNP) data.

Main Results:

• STR analysis successfully separated isolates into four clades, consistent with WGS analysis.
• The optimized STR assay identified 32 distinct genotypes.
• Isolates differing by >50 SNPs were distinguished by at least one STR marker.

Conclusions:

• The optimized STR panel is a validated, reliable, and high-resolution tool for C. auris genotyping.
• This method aids in investigating C. auris outbreaks and understanding transmission dynamics.
• STR genotyping offers a powerful alternative to WGS for routine C. auris surveillance.