Analysis of strain relatedness using high resolution melting in a case of recurrent candiduria.
BACKGROUND
Several genotyping protocols have been described to study Candida albicans strains with different sensitivity values. In this study we have analyzed the genetic relatedness and the antifungal susceptibility of several Candida albicans strains isolated from a patient who from suffered recurrent candiduria for a period of five years. Strains were genotyped using Microsatellite Length Polymorphism (MLP) with three microsatellite markers (HIS 3, EF 3 and CDC 3), and a new method based on high resolution melting (HRM) was developed to analyze the microsatellite region. This method was compared with the conventional technique that uses capillary electrophoresis.


RESULTS
MICs of the isolates showed the existence of fluconazole susceptible and resistant strains. An inter-colony test using single concentration (8 and 16 mg/l) of fluconazole revealed the coexistence of both fluconazole susceptible and resistant strains. Both genotyping analysis methods showed that all the patient's isolates had a clonal origin. HRM analysis method developed was able to accurately establish strain relatedness and presented a discriminatory power of 0.77.


CONCLUSIONS
Although HRM analysis method presented a lower discriminatory power compared to methods based on capillary electrophoresis, it provided a more cost-effective and suitable alternative for genotyping C. albicans in a clinical laboratory.
Servicio de Micología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Ctra Majadahonda-Pozuelo, Km 2, Majadahonda, Madrid, 28220, Spain.
Sara
S
Gago
Belen
B
Lorenzo
Alicia
A
Gomez-Lopez
Isabel
I
Cuesta
Manuel
M
Cuenca-Estrella
Maria J
MJ
Buitrago
D000935:Antifungal Agents / Q000494:pharmacology; D002176:Candida albicans / Q000145:classification* / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*; D002177:Candidiasis / Q000382:microbiology*; D003365:Costs and Cost Analysis; D004271:DNA, Fungal / Q000235:genetics*; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D058889:Molecular Typing / Q000191:economics / Q000379:methods*; D016533:Mycological Typing Techniques / Q000191:economics / Q000379:methods*; D012008:Recurrence; D044366:Transition Temperature
D000935:Antifungal Agents; D004271:DNA, Fungal