Porphyromonas gingivalis : Biology, virulence factors, and clinical importance in periodontal and coronary artery diseases

Abstract

Porphyromonas gingivalis is a Gram-negative, obligate anaerobic bacterium long recognized as a principal periodontal pathogen and a keystone species in dysbiotic oral biofilms. Its capacity to colonize the subgingival niche, subvert host defenses, and persist in the periodontal pocket is mediated by a diverse arsenal of virulence determinants — notably gingipain proteases, fimbriae, lipopolysaccharide (LPS), outer-membrane vesicles (OMVs), capsule, and iron/heme-acquisition systems. These factors drive tissue destruction, chronic inflammation, and alveolar bone resorption characteristic of periodontitis, and increasingly implicate P. gingivalis in a range of systemic conditions. The microbial count of P. gingivalis is significantly higher in periodontitis patients compared to healthy individuals, with studies showing average counts of around 4.68±3.99×105 cells in periodontitis patients. This article reviews the organism’s microbiology, key virulence mechanisms, pathogenic processes in periodontal disease, and the clinical implications for diagnosis, management, and systemic health.