Biofilms are sticky, mat-like microbial communities found throughout nature and many parts of the human body. They typically consist of hundreds of distinct organisms that cooperate with each other to adapt to changes in their environment, such as shifts in pH or the mechanical stress of motion, and ensure their mutual survival. "With biofilms, the sum is definitely greater than the individual parts," said Nelson.

To date, researchers have identified over 400 bacteria in the oral biofilm, but they estimate this number may represent just over half of the microbes there. Scientists say this shortfall owes to the fact that many of these microbes cannot be cultivated in the laboratory or recovered in pure form, making it extremely difficult to understand how the biofilm functions as an intact community or identify the subsets of microbes that interact to cause oral infections.

Gill said previous sequencing projects of medically important microbes, such as the pathogens that cause tuberculosis, gonorrhea, and cholera, already have provided a wealth of information to researchers. Included among these new leads are a more detailed understanding of their physiology, virulence, and potential vulnerabilities.

However, because the oral cavity houses not one but hundreds of bacteria that interact to cause disease, some have sought new approaches that comprehensively evaluate the complete biological capabilities of the various microbes there. This more global view may lead to novel insights into the interactions among these microbes that maintain oral health or cause disease, such as periodontitis.

In the newly launched NIDCR-supported study, the scientists will employ metagenomics, an investigative strategy first proposed nearly 20 years ago but which has become increasingly popula
'"/>

Contact: Bob Kuska
kuskar@nidcr.nih.gov
301-594-7560
NIH/National Institute of Dental and Craniofacial Research
7-Dec-2004