Comparison between phenotypic characterization and semi-nested PCR for the identification of Candida species in clinical isolates

Abstract

Background: Nowadays, due to the increasing number of immunocompromised patients, mycosis infections caused by Candida species are on the rise, especially among hospitalized patients. Objectives: In the current study, the chromogenic medium CHROMagar™ Candida and semi-nested polymerase chain reaction (snPCR) were compared concerning their ability to detect the species of Candida in 65 clinical isolates. Materials and Methods: We used snPCR with universal and species-specific primers to detect Candida species in the culture of clinical isolates. By using universal primers, we carried out the amplification of the 3/end of 5.8S ribosomal DNA (rDNA) and the 5/end of 28S rDNA, including the internal transcribed spacer 2 (ITS2) and production of 350 to 410-bp fragments from 4 Candida species, vis. Candida albicans, Candida tropicalis, Candida glabrata, and Candida parapsilosis. Results: The phenotypic identification system identified 60 (92.3%) yeasts isolates, including C. albicans (n = 33), C. glabrata (n = 14), C. tropicalis (n = 11), and C. parapsilosis (n = 2), and 5 isolates were mixed culture. By snPCR, 63 (96.6%) isolates were identified, including C. albicans (n = 37), C. glabrata (n = 11), C. tropicalis (n = 14), and C. parapsilosis (n = 1), and the species of 2 isolates could not be identified. Additionally, snPCR for the specific identification of the Candida species of the 65 clinical Candida isolates revealed 70.3% results agreement with the chromogenic medium CHROMagar™ Candida. Conclusions: In this study, snPCR was specific and more sensitive than the chromogenic medium CHROMagar™ Candida for the detection of Candida spp. insofar as it failed to identify only a few isolates. Copyright