Fusobacteria as a Bridge between Health and Disease: a Metatranscriptomic Approach

Fusobacterium nucleatum is an oral anaerobe and the most common gram-negative isolate from both healthy and diseased oral sites. Association of F. nucleatum with gingivitis and with its progression to periodontal disease has been based on the fact that numbers of F. nucleatum organisms greatly increase in samples taken from diseased sites compared to those from healthy ones. The author feels that the sharing of both gram-positive and gram-negative properties might facilitate communication of fusobacteria with both gram-positive early colonizers and gram-negative late colonizers, an essential stage in the development of the periopathogenic dental biofilm. The species complexity of oral biofilms is probably the greatest hurdle in studying the fusobacterial role in oral health and disease. The author proposes that fusobacterial virulence relies on the presence of its adhesins and not on classical toxins and proteases. Microarrays can be designed to interact uniquely with F. nucleatum gene transcripts. These microarrays can be reacted with total RNAs extracted from dental biofilms sampled from healthy and diseased periodontal sites of increasing disease severity. In vitro studies have suggested that fusobacterial bridging coaggregation interactions are important for the shift in the composition of the microbial community associated with transition from health to disease. Ongoing introduction of tools for genetic manipulation of fusobacteria will enable the investigation of fusobacterial virulence-associated molecular elements. Integration species-specific and general molecular tools is expected to enable the study and the understanding of F. nucleatum's role in bridging from oral health to disease