Diagnostic Value of The Real-Time PCR Test for The Identification of Candida Species in Oral Rinse Solutions

Abstract

Objective: A variety of microorganisms are found in the oral cavities of healthy humans, including yeast fungi. Disruption of the balance among these microorganisms may cause excessive yeast colonization, or oral candidosis. In the present study, we aimed to investigate the diagnostic value of a real-time PCR method for the identification of medically important Candida species in the oral flora. Methods: Two hundred students from Çukurova University Faculty of Dentistry participated in this study. The concentrated oral rinse water samples from the participants were inoculated into CHROMagar Candida (CAC) medium with a swab. CAC along with RT-PCR and MALDI-TOF MS were used to identify the Candida species. Results: A total of 68 yeast fungi were isolated from 52 (26%) clinical samples. The most common isolated species were C. albicans (36.1%), C. parapsilosis (21.3%), C. dubliniensis (14.7%), C. lusitaniae (9.8%), C. kefyr (8.2%), C. lambica (3.3%) and other Candida species (6.6%). Oral colonisation of yeast fungi was associated with the toothpaste brand (p=0.02). The Candida species isolated in this study were reliably identified by RT-PCR melting curve analysis (MCA), except C. albicans, C. kefyr and C. lambica. However, this method could not distinguish C. albicans and C. kefyr based on their peak melting temperatures (Tm). Conclusion: It may take 2-3 days for Candida species to be identified and differentiated from each other using conventional methods. MCA of Candida species using RT-PCR, which can be accomplished in a single day, is a simple, inexpensive, and rapid method. However, this study revealed that RT-PCR was not reliable in the identification of Candida species (C. albicans, C. kefyr, and C. lambica).