Oral microbiology is the study of the microorganisms of the oral cavity and the interactions between the oral microorganisms with each other and with the host. Of particular interest is the role of oral microorganisms in the two major dental diseases: dental caries and periodontal disease.
The mouth harbors a diverse, abundant and complex microbial community. This highly diverse microflora inhabits the various surfaces of the normal mouth. Bacteria accumulate on both the hard and soft oral tissues in biofilms. Bacterial adhesion is particularly important for oral bacteria.
Oral bacteria have evolved mechanisms to sense their environment and evade or modify the host. Bacteria occupy the ecological niche provided by both the tooth surface and gingival epithelium. However, a highly efficient innate host defense system constantly monitors the bacterial colonization and prevents bacterial invasion of local tissues. A dynamic equilibrium exists between dental plaque bacteria and the innate host defense system.
Oral bacteria include streptococci, lactobacilli, staphylococci, corynebacteria, and various anaerobes in particular bacteroides. The oral cavity of the new-born baby does not contain bacteria but rapidly becomes colonized with bacteria such as Streptococcus salivarius. With the appearance of the teeth during the first year colonization by Streptococcus mutans and Streptococcus sanguinis occurs as these organisms colonise the dental surface and gingiva. Other strains of streptococci adhere strongly to the gums and cheeks but not to the teeth. The gingival crevice area (supporting structures of the teeth) provides a habitat for a variety of anaerobic species. Bacteroides and spirochetes colonize the mouth around puberty.
The Forsyth Institute has launched a new one-of-a-kind service for the research community. The Forsyth Microbial Identification Microarray Service (MIM) enables the rapid identification of bacterial species in clinical samples. The first service offering, Human Oral Microbe Identification Microarray (HOMIM), will focus on detection of bacterial profiles from the oral cavity. Researchers can use this service to compare bacterial associations in health vs. disease, monitor the effects of therapy on the oral ecology and perform microbial perturbation studies.
The Forsyth research team led by Drs. Bruce Paster and Floyd Dewhirst has used molecular analyses based on 16S rRNA sequencing to identify 550 oral bacterial species. Using this information, they have developed HOMIM, which allows the simultaneous detection of about 300 of the most prevalent oral bacterial species, in a single hybridization. This high throughput technology will allow the evaluation of species that cannot yet be grown in vitro. Information about the service can be found online at www.forsyth.org/mim.
HOMIM is available to researchers from academic institutions as well as private corporations. Researchers can submit DNA isolated from clinical samples and receive an online comprehensive analysis and report. Results can typically be obtained within days once processing has begun.
