Profiling the Human Oral Mycobiome in Tissue and Saliva Using ITS2 DNA Metabarcoding Compared to a Fungal-Specific Database.

The advent of high-throughput sequencing has caused a paradigm shift from the one-pathogen one-disease model to the significance of dysbiosis of the oral microbiome, including the oral mycobiome. The oral mycobiome can be profiled by a method modified from that used to profile the bacteriome with 16S rRNA gene primers. The first modification is to include an initial fungus lysis step that ensures representative yields of fungal DNA. The second step is to use a reliable target, the ITS1 and/or ITS2 regions of the 23S rRNA, to define the oral fungal population, and modifications of library preparation required to deal with the variable sized amplicons generated. In this chapter, a proven microbiomic approach to identify fungal populations in oral tissue samples associated with cancer is described. This approach is also applicable to the study of the salivary mycobiome in both healthy and diseased individuals.