Fusobacterium nucleatum Role — MFDS Part 1 MCQ
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Correct answer: B — Adhesin-mediated coaggregation with both early Gram-positive colonisers and later anaerobic species
Fusobacterium nucleatum is a bridging organism in dental plaque. Its surface adhesins permit coaggregation with early colonisers, including oral streptococci and Actinomyces, as well as later-colonising anaerobic periodontal taxa. This broad range of interspecies interactions helps integrate organisms that otherwise have limited direct recognition and contributes to the spatial maturation of the biofilm. It is not normally the first organism to bind the acquired pellicle; streptococci and Actinomyces are major primary colonisers. Insoluble glucan synthesis from sucrose is particularly associated with cariogenic streptococci rather than F. nucleatum. Antimicrobial resistance may occur in individual isolates but does not explain its central ecological role, and phagocyte evasion is not the principal mechanism by which it promotes plaque development.
Reference: Chen Y, Shi T, Li Y, Huang L, Yin D. Fusobacterium nucleatum: The Opportunistic Pathogen of Periodontal and Peri-Implant Diseases. Figure 1: bridging function in biofilm formation. Frontiers in Microbiology. 2022. https://pubmed.ncbi.nlm.nih.gov/35369522/