Genome of Gum Disease Bacterium Sequenced
By Susan Johnson
Scientists have sequenced the genome of Porphyromonas gingivalis, a bacterium believed to play a major role in adult periodontitis, or gum disease. It is the first oral disease-causing microbe to be completely sequenced. The annotated P. gingivalis sequence was recently posted on the Internet, making it freely available to researchers worldwide.
The sequencing project, supported by the National Institute of Dental and Craniofacial Research, was carried out by scientists at the Institute for Genomic Research in Rockville in collaboration with the Forsyth Institute in Boston.
"P. gingivalis is one of the most intensely studied dental pathogens," said Dr. Dennis Mangan, chief of NIDCR's Infectious Diseases and Immunity Branch. "There is a large cadre of researchers out there ready to use the sequence data to identify the genetic mechanisms for the organism's virulence and to develop better approaches for preventing or eradicating periodontitis."
Periodontitis is a chronic infectious disease of the gums and underlying bony tissues. Untreated, it can destroy those tissues and result in tooth loss. By conservative estimate, more than 35 million Americans have periodontitis.
The mouth is teeming with bacteria, most of which do not cause disease. But when the largely gram-positive community of bacteria that normally live in the spaces between the gums and teeth are displaced by gram-negative anaerobic bacteria, periodontitis sets in. A small number of gram-negative species are associated with specific forms of periodontitis; P. gingivalis is the organism associated with chronic and severe adult periodontitis.
With the genetic blueprint for P. gingivalis in hand, dental researchers will be able to identify potential targets for periodontal vaccines and drug therapies.
The P. gingivalis genome is available on the Comprehensive Microbial Resource web site at http://www.tigr.org/tigr-scripts/CMR2/CMRHomePage.spl.
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