A comparison between CHROMagar, PCR-RFLP and PCR-FSP for identification of Candida species

Background and Purpose: The epidemiological alteration in the distribution of Candida species, as well as the significantly increasing trend of either intrinsic or acquired resistance of some of these fungi highlights the need for a reliable method for the identification of the species. Polymerase chain reaction (PCR) is one of the methods facilitating the quick and precise identification of Candida species. The aim of this study was to compare the efficiency of CHROMagar, PCR-restriction fragment length polymorphism (PCR-RFLP), and PCR-fragment size polymorphism (PCR-FSP) assays in the identification of Candida species to determine the benefits and limitations of these methods. Materials and Methods: This study was conducted on ۱۰۷ Candida strains, including ۲۰ standard strains and ۸۷ clinical isolates. The identification of the isolates was accomplished by using CHROMagar as a conventional method. The PCR-RFLP assay was performed on the entire internal transcribed spacer (ITS) region of ribosomal DNA (rDNA), and the consequent enzymatic digestion was compared with PCR-FSP results in which ITS۱ and ITS۲ regions were separately PCR amplified. In both molecular assays, yeast identification was carried out through the specific electrophoretic profiles of the PCR products. Results: According to the results, the utilization of CHROMagar resulted in the identi-fication of ۲۹ (۳۳.۳%) Candida isolates, while the PCR-RFLP and PCR-FSP facilitated the identification of ۸۳ (۹۵.۴%) and ۸۰ (۹۱.۹%) isolates, respectively. The obtained concordances between CHROMagar and PCR-RFLP, between CHROMagar and PCR-FSP, as well as between PCR-RFLP and PCR-FSP were ۰.۲۰, ۰.۲۳, and ۰.۷۷, respectively. Conclusion: The recognition of the benefits and limitations of PCR methods allows for the selection of the most efficient technique for a fast and correct differentiation. The PCR-RFLP and PCR-FSP assays had satisfactory concordance. The PCR-FSP provides a rapid, technically simple, and cost-effective method for the identification of Candida species. Nevertheless, to accurately differentiate among the taxonomically related species, PCR-RFLP should be implemented.

Keywords:

Candida species , Identification , PCR-fragment size polymorphism , PCR-restriction fragment length polymorphism