Overview of the oral microbiome
Compared to tissue, blood, and fecal matter, saliva is a more accessible and non-invasive resource as a biospecimen. However, it is utilized lesser due to the lack of standardization protocols and limited knowledge on biomolecule variability in salivary samples. Additionally, different saliva sample types vary in composition which affects analytical accuracy despite existing advanced techniques. With the identification of several biomarkers, salivary DNA-based methods are now used to screen for mutations related to cancer and other hereditary disorders.
Why is the oral microbiome important?
The microbiome plays vital roles in biological processes such as protection and disease initiation and progression. The oral cavity contains the most abundant microbiome after the gastrointestinal tract. However, compared to other sub-microbiomes, the oral cavity is the most understudied but has a huge potential for growth in research interest. The oral microbiome can remain stable over time in healthy individuals which makes it a good candidate for correlation studies featuring disease recurrence, onset, and progression. Considering the potential interactions of the gut and oral microbiome, there can be multitudes of disease outcomes. However, it is important to note that several studies have pointed out the relatively increased resilience of the oral microbiome against antibiotic resistance and disturbance. Although the mechanisms behind this are still unknown, knowing the high intrinsic resiliency of the oral microbiome might give us a blueprint of a treatment that can be applied to multiple parts and diverse individuals.
In the state of balance, the oral biofilm forms a thin, protective, odorless film making teeth clean and gums healthy. An imbalance is usually correlated to tooth decay and gum disease. In fact, periodontal health has been linked to the progression of cardiovascular diseases. Aside from oral diseases, growing evidence shows that alterations in the oral microbiome have potential diagnostic applications. Specific bacterial combinations and frequencies have been linked to the occurrence of certain diseases. As more studies elucidate salivary composition in varying disease states, more saliva-based diagnostic and therapeutic methods will follow.
How to study the oral microbiome?
The collection method for saliva samples does not affect the subsequent compositional analysis. It usually involves collection through spitting and then cellular collection and lysis. For each individual sample, the variables such as traits, diet, and health should be known from the source organism. Genomic DNA quantity and quality are checked followed by quantitative PCR using a bacterial 16S primer set. Lastly, the 16S rRNA gene amplicons will be sequenced by Illumina MiSeq system for next-generation sequencing. From here, statistical analysis featuring comparative and multivariate analyses could be conducted to see correlations, clusters, and taxonomic profiles.
The advent of NGS paved the way for correlation studies using the oral microbiome through saliva. In one study, dysbiosis in the oral microbiota revealed bacterial species contributing to lung cancer in non-smokers. In a separate study, microbes were identified to be associated with primary Sjögren’s syndrome. miRNA and microbiome dysregulations discovered in the saliva of children with autistic spectrum disorder are associated with cognitive impairments. Urbanization and obesity have been also linked with dysbiosis in the oral microbiome. These findings only prove the versatility of potential saliva-based diagnostic techniques.
About CD Genomics
CD Genomics provides the research community with high-quality high-throughput sequencing, genotyping, microarray, and population genetics services. Through more than a decade of hard work, CD Genomics has become an influential company in the industry and continues to innovate, keeping up with the forefront of scientific research and leading the latest and most comprehensive genomics technical support.
