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TAXONOMY: Bacteroidetes/Chlorobi group -> Bacteroidetes -> Bacteroidia -> Bacteroidales -> Porphyromonadaceae -> Porphyromonas -> Porphyromonas gingivalis
Identified as a constituent of the oral microbiome by Human Oral Microbiome Database. Identified as constituent of vaginal microbiome. [PMID:23282177] Porphyromonas gingivalis belongs to the phylum Bacteroidetes and is a nonmotile, Gram-negative, rod-shaped, anaerobic, pathogenic bacterium. It forms black colonies on blood agar. It is found in the oral cavity, where it is implicated in certain forms of periodontal disease, as well as the upper gastrointestinal tract, respiratory tract, and in the colon. It has also been isolated from women with bacterial vaginosis. Collagen degradation observed in chronic periodontal disease results in part from the collagenase enzymes of this species. It has been shown in an in vitro study that P. gingivalis can invade human gingival fibroblasts and can survive in them in the presence of considerable concentrations of antibiotics. P. gingivalis also invades gingival epithelial cells in high numbers, in which cases both bacteria and epithelial cells survive for extended periods of time. High levels of specific antibodies can be detected in patients harboring P. gingivalis. In addition, P. gingivalis has been linked to rheumatoid arthritis. It contains the enzyme peptidyl-arginine deiminase, which is involved in citrullination. Patients with rheumatoid arthritis have an increased incidence of periodontal disease and antibodies against the bacterium are significantly more common in these patients.
This species has been identified as a resident in the human gastrointestinal tract based on the phylogenetic framework of its small subunit ribosomal RNA gene sequences.[PMC 4262072]