Give an example of a bridging organism that links early and late colonizers via coaggregation.

Give an example of a bridging organism that links early and late colonizers via coaggregation.

• A. Streptococcus mutans
• B. Fusobacterium nucleatum
• C. Porphyromonas gingivalis
• D. Actinomyces israelii

Answer: (B)

Bridging organisms in oral biofilms connect early colonizers to late colonizers, enabling the community to mature from a simple initial layer to a complex, multi-species plaque. Fusobacterium nucleatum is the classic example because its surface adhesins recognize and bind to both early colonizers (such as Streptococcus species) and late colonizers (like Porphyromonas gingivalis). This dual coaggregation allows it to act as a bridge, linking the antibiotic-friendly, oxygen-tiered early layer with the anaerobic, late-colonizing organisms that dominate mature biofilms. By facilitating this integration, it supports the progression and stability of the biofilm structure. The other organisms listed are mainly early colonizers or late colonizers themselves and do not typically serve this bridging role.

Bridging organisms in oral biofilms connect early colonizers to late colonizers, enabling the community to mature from a simple initial layer to a complex, multi-species plaque. Fusobacterium nucleatum is the classic example because its surface adhesins recognize and bind to both early colonizers (such as Streptococcus species) and late colonizers (like Porphyromonas gingivalis). This dual coaggregation allows it to act as a bridge, linking the antibiotic-friendly, oxygen-tiered early layer with the anaerobic, late-colonizing organisms that dominate mature biofilms. By facilitating this integration, it supports the progression and stability of the biofilm structure. The other organisms listed are mainly early colonizers or late colonizers themselves and do not typically serve this bridging role.