Surface ultrastructure of some oral bacteria

Area of Science:

• Oral microbiology
• Bacterial adhesion
• Microbial ecology

Background:

• Dental plaque formation involves complex interactions between oral bacteria.
• Understanding initial bacterial adhesion and interspecies cohesion is crucial for oral health.

Purpose of the Study:

• To investigate the adhesion mechanisms of Streptococcus sanguis, Fusobacterium nucleatum, and Actinomyces sp. to enamel and epon.
• To examine the interspecies cohesion between these oral bacteria.

Main Methods:

• Scanning and transmission electron microscopy were used to visualize bacterial adhesion and cohesion.
• Enamel and epon surfaces were coated with salivary macromolecules prior to bacterial exposure.
• Various staining techniques were employed to study cell surface morphology.

Main Results:

• Streptococcus sanguis adhered to a salivary pellicle, with Fusobacterium nucleatum and Actinomyces sp. attaching to S. sanguis or the pellicle.
• Fimbriae on S. sanguis appeared to unfold at contact points.
• Pilus-like fimbriae on F. nucleatum and dense fimbriae on Actinomyces sp. were implicated in interspecies cohesion.

Conclusions:

• Specific bacterial surface structures, particularly fimbriae, play a critical role in the adhesion and co-aggregation of oral bacteria.
• These findings contribute to understanding the initial stages of dental biofilm formation.