Introduction to Oral Microbiome

Flashcards covering the fundamentals of the human oral microbiome, including key terminology, sequencing technologies, and the ecological succession of dental plaque.

Superorganism

An entity whose metabolism represents an amalgamation of microbial and human attributes, characterized by $100$ trillion bacteria colonizing the human body.

Holobiont

The host organism and all its symbiotic microbial residents.

Microbiome

All microorganisms in a particular habitat and their collective genomes.

Integrative metabolism

The process of putting together human metabolism and the metabolism of our resident microbes.

Microbial-to-Human cell ratio

A ratio of $10$ bacteria to every $1$ human cell.

Sanger sequencing

A sequencing technique that processes only one sequence at a time, producing long reads up to $1,500\,bp$ with $99.99\%$ accuracy.

Next generation sequencing (NGS)

A massively parallel sequencing technology that allows millions of fragments to be sequenced in one run with high throughput.

Metagenomics

Open-ended molecular techniques used to explore microbial community composition and genetic makeup, identifying both cultivable and non-cultivable species.

Human Microbiome Project (HMP)

A project that used comprehensive characterization to study the microbiome in $18$ sites of the human body, including $9$ sites in the mouth.

$$16s$$

A gene present in all bacteria with a sequence that differs from one bacterium to another, used for identification.

Dental plaque

A soft, tenacious deposit that forms on tooth surfaces and is not readily removed by rinsing with water.

Pioneer species

The initial microorganisms to colonize the oral cavity, primarily aerobic Gram-positive Streptococcus species.

Autogenic succession

Microbial succession caused by microbial factors, where pioneer species modify the environment for subsequent species.

Allogenic succession

Microbial succession caused by non-microbial factors, such as the eruption of teeth, placement of appliances, or dietary shifts.

Early colonizers

Mainly facultative Gram-positives, such as Actinomyces naeslundii and Streptococcus sanguinis.

Secondary colonizers

Capnophilic or anaerobic Gram-negative bacteria like Capnocytophaga spp., Veillonella spp., Prevotella spp., and Fusobacterium nucleatum.

Microbial homeostasis

A state of high stability in oral microbial communities resulting from a balance of dynamic synergistic and antagonistic interactions.

Dysbiosis

A disruption of microbial community homeostasis characterized by imbalanced composition and function, leading to disease.

Capnophilic

Microorganisms that are $CO_2$ loving, such as Haemophilus, Capnocytophaga, and Aggregatibacter.

Core Microbiome

Species found in the majority of the population.

Core oral phyla

The dominant bacterial phyla in a healthy oral cavity, which include Firmicutes, Proteobacteria, Bacteroidetes, Actinobacteria, and Fusobacteria.