Filifactor alocis(F.alocis), a non-sporeforming, obligately anaerobic rod Gram-positive type of bacteria, was recently discovered from the gingival sulcus of patients with gingivitis and periodontitis. F.alocis grows well when cultured in brain–heart infusion broth supplemented with hemin, Vitamin K, cysteine, and arginine at 37 ℃ under anaerobic conditions but exhibits slow and sparse growth and is relatively biochemically inert. F.alocis can be isolated from caries, endodontic infections, and types of periodontitis. This condition indicates that F.alocis has a close relationship with these diseases. Under conventional anaerobic culture conditions, the generation time of F.alocis is longer than that of Porphyromonas gingivalis. However, a medium supplemented with lysine, threonine, valine, isoleucine, glycine, and cystine contributes to the growth of F.alocis. Coculturing F.alocis with both enhances biofilm formation, the ability to adhere, and the invasion of HeLa cells. F.alocis is distributed at the bottom of the periodontal pocket at the tissue side; it induces the secretion of pro-inflammatory cytokines except for interleukin-8 from gingival epithelial cells and helps avoid host immune defense. F.alocis clinical isolates D-62D are more virulent compared with F.alocis ATCC35896.
