Query: NC_015760:8914 Streptococcus salivarius CCHSS3, complete genome
Lineage: Streptococcus salivarius; Streptococcus; Streptococcaceae; Lactobacillales; Firmicutes; Bacteria
General Information: The commensal bacterium Streptococcus salivarius is predominant specie of the human oropharyngeal tract and exerts an important role in oral ecology. Streptococcus salivarius is an aerobic, gram-positive coccus. This organism is the most common organism isolated from the human oral cavity. Streptococcus salivarius can also be an opportunistic pathogen causing endocarditis, blood infection, and peritonitis. Streptococci are Gram-positive, nonmotile, nonsporeforming, catalase-negative cocci that occur in pairs or chains. Members of this genus vary widely in pathogenic potential. Most streptococci are facultative anaerobes, and some are obligate anaerobes.
Subject: NC_015571:1265121 Porphyromonas gingivalis TDC60, complete genome
Lineage: Porphyromonas gingivalis; Porphyromonas; Porphyromonadaceae; Bacteroidales; Bacteroidetes; Bacteria
General Information: This organism is associated with severe and chronic periodontal (tissues surrounding and supporting the tooth) diseases. Progression of the disease is caused by colonization by this organism in an anaerobic environment in host tissues and severe progression results in loss of the tissues supporting the tooth and eventually loss of the tooth itself. The black pigmentation characteristic of this bacterium comes from iron acquisition that does not use the typical siderophore system of other bacteria but accumulates hemin. Peptides appear to be the predominant carbon and energy source of this organism, perhaps in keeping with its ability to destroy host tissue. Oxygen tolerance systems play a part in establishment of the organism in the oral cavity, including a superoxide dismutase. Pathogenic factors include extracellular adhesins that mediate interactions with other bacteria as well as the extracellular matrix, and a host of degradative enzymes that are responsible for tissue degradation and spread of the organism including the gingipains, which are trypsin-like cysteine proteases.