Filifactor alocis: The Newly Discovered Kid on the Block with Special Talents

Abstract

Infection-induced periodontal disease has been primarily focused on a small group of periodontal pathogens. A paradigm shift, based on data emerging from the oral microbiome project, now suggests the involvement of as-yet-unculturable and fastidious organisms. Collectively, these studies have demonstrated that there are changes in the periodontal status associated with shifts in the composition of the bacterial community in the periodontal pocket. In addition, it is likely that the emerging new pathogens may play a more significant role in the disease. One of the organisms previously unrecognized is Filifactor alocis. While this Gram-positive anaerobic rod has been identified in peri-implantitis, in endodontic infections, and in patients with localized aggressive periodontitis, its presence is now observed at significantly higher levels in patients with adult periodontitis or refractory periodontitis. Its colonization properties and its potential virulence attributes support the proposal that F. alocis should be included as a diagnostic indicator of periodontal disease. Moreover, these emerging characteristics would be consistent with the polymicrobial synergy and dysbiosis (PSD) periodontal pathogenesis model. Here, unique characteristics of F. alocis are discussed. F. alocis has specific factors that can modulate multiple changes in the microbial community and host cell proteome. It is likely that such variations at the molecular level are responsible for the functional changes required to mediate the pathogenic process.

Characterization of Filifactor alocis and its immune evasion strategies employed against human neutrophils.

“…Periodontitis is defined as an infection-induced chronic inflammatory disease impacting the tissues supporting the teeth (1,2). Periodontal tissues are easily accessible to both bacteria and immune host cells, as it is comprised of a porous membrane of gingival epithelia cells with no protective mucous layer, as observed in the intestinal epithelium (1,3,4).…”

“…It is constantly utilized for passage of air and food, which will travel through the body systemically to its target site, however, microorganisms present will also use this transport to spread along the contiguous epithelial surfaces (14). Therefore, clear evidence is now available linking periodontitis to a number of systemic infections and diseases, such as cardiovascular disease, stroke, preterm birth, diabetes and pneumonia (2,14).…”

“…alocis is a gram-positive, asaccharolytic, fastidious, rod that grows under obligate anaerobic conditions (2,54). This bacterium was first isolated from clinical patients afflicted with gingivitis and periodontitis in 1985 and given the name Fusobacterium alocis, before being reclassified in 1999 to Filifactor (2,55).…”

“…F. alocis has been associated with several oral conditions like peri-implantitis, and endodontic infection, however, it is now known to be linked to the development of periodontal disease. It is found to be significant to the pathogenic biofilm produced in a disease setting, can establish synergistic relationships with other oral pathogens, and possesses potential virulence properties like oxidative stress resistance, that allow it to effectively colonize, survive and out-compete other periodontal pathogens (2,57). Studies performed by Dahlen et al have determined F. alocis a species relevant in routine diagnostics for periodontal disease and this bacterium is also found to be associated with other oral pathogens such as P. gingivalis, Streptococcus gordonii (S. gordonii),…”

“…In patients with periodontal disease, F. alocis is often present and it has been proposed that this bacterium should serve as a diagnostic indicator of the disease (2,50,52,54,59). Moreover, F. alocis is absent in healthy patients (2).…”