Identification of Candida Species Associated with Blood Infection by Multiplex PCR and Phenotypic Characteristics

 The correct identification of Candida species is one of the most critical procedures in prognostic and therapeutic significance, allowing an early and appropriate antifungal therapy. This study aimed to evaluate multiplex PCR as a rapid diagnostic method and traditional phenotypic tests in identifying Candida species isolated from candidemia cases.

 In this study, 38 Candida spp were isolated from culturing of human blood obtained from patients suspected to candidemia. The isolated species were evaluated by phenotypic and molecular methods including carbohydrate assimilation test, colony colour on CHROMagar Candida, chlamydoconidia production, germ tube formation and Multiplex PCR. Multiplex PCR was performed using specific primers of 4 common species. The results of multiplex PCR were compared with those obtained from phenotypic tests.

 According to multiplex PCR findings, the isolated Candida species were identified as C. albicans, C. parapsilosis, C. glabrata, and C. tropicalis. Phenotypic tests identified that 23 (60.52%), 8 (21.05%), 5 (13.15%), and 2 (5.26%) isolates belonged to C. albicans, C. parapsilosis, C. glabrata, and C. tropicalis, respectively, that were confirmed by multiplex PCR results. C. albicans and C. parapsilosis had the same carbohydrate assimilation pattern but were differentiated based on their colonies color on CHROMagar and the ability of C. albicans to produce chlamydoconidia and germ tube. C. glabrata (100%) and C. tropicalis (100%) assimilated trehalose and cellobiose, respectively.

 Our study showed that the both phenotypic and molecular techniques provide appropriate information for identification of Candida spp from blood samples.