Phase variable restriction modification systems in the genome sequences of periodontal pathogens Prevotella intermedia, Tannerella forsythia and Porphyromonas gingivalis. Bacteria

Periodontal disease encompasses a range of mild to severe inflammatory oral bacterial infections which in chronic cases can lead to the destruction of the tissues supporting the teeth. There is known to be a diverse mix of upwards of 700 species of gram positive and gram negative bacteria in the oral cavity; however the onset of periodontal disease is characterised by a shift of the normal microflora towards gram negative proteolytic anaerobes. Key amongst these organisms is the obligate anaerobe Porphyromonas gingivalis, a member of the “red complex”, which has been identified in greater than 85% periodontal infections studied. Our study has determined the whole genome sequences for eighteen oral pathogens, including Porphyromonas gingivalis, Prevotella intermedia and Tannerella forsythia strains, all of which were isolated from the periodontal pockets of patients with advanced periodontal disease.