While our oral cavity is the initiating point of food digestion process, it is also the habitat for hundreds of microorganisms Those microorganisms found in the oral cavity include bacteria, fungi, viruses and protozoa. Although most of the microorganisms are beneficial to the human body, certain oral microbes can cause diseases such as tooth cavities, gum diseases, bad breath etc. Within the oral cavity, there are various microenvironments, e.g. cheek, gingiva, lower and upper mouth floors, throat, tongue, saliva, and teeth. Identification of the microbiome present in the oral cavity is vital to understand the role of those microorganisms on human health and diseases. Oral microbiomes are the most studied group of microorganisms in human body because of ease of sampling. Like in other human body part, the oral cavity also possesses core and variable microbiomes. The core microbiomes are found in all individuals, while the variable microbiomes are unique to individuals.
Earlier, the identification of microbiome was based on conventional methods such as culture-based techniques. The major drawback of this technique is that it is very time consuming and it misses many taxa as they could not be cultured. Recently, with the advancement of genomic technologies including next generation sequencing, scientists have overcome those limitations. According to expanded Human Oral Microbiome Database (eHOMD), currently, 771 microbial species identified. Out of the 771 species, 439 (57%) are officially named, 100 (13%) are unnamed but cultivated, and 231 (30%) are identified as uncultivated phylotypes. There are 1570 genomes of the oral microbiomes available in the database. That represents at least one reference genome for 475 taxa which is 62% of all taxa and 85% of the cultured taxa. The number of genomes in the database clearly shows that more and more scientists are adopting the genomic approach to identify microbiomes.
The oral cavity microbiomes are comprised mostly of bacteria which are represented mainly by two groups i.e. Firmicutes and Bacteroidetes. Firmicutes are predominantly comprised of the genus Streptococcus, while Bacteroidetes consisted of Prevotella and Proteobacteria. There are 85 species of fungi identified in the oral cavity. Those fungal species mainly correspond to the genus Candida, Cladosporium, Aureobasidium and Sccharomcetales. Among viruses, human herpesvirus (HHV) and human papillomavirus (HPV) are common in the oral cavity. The common protozoa found in the oral cavity mainly belong to the genus Entamoeba and Trichomonas.
When the diversity of the oral microbiomes is compared with the microbiomes found in other human body organs, the oral cavity possesses the second largest microbial community after the gut. When the microbial diversity of different parts within the oral cavity is compared, the highest diversity of microbiomes is found in saliva and the gingival plaque, while the lowest diversity was found in the keratinized gingiva.
If you are interested in knowing who is living in between those pearly whites, feel free to contact us. We are the expert on that because we are one of the pioneer companies in microbial sequencing. You just need to swab the circumference of the inside of the mouth and put that swab in a sterile container (tube or vial) and send to us. We will extract the DNA from the swab and perform sequencing with the state-of-the-art sequencing technology. Once the sequencing is done, our proficient bioinformatic team will analyze the sequence data to identify the microbes.