Growth, development, and gene expression in a persistent Streptococcus gordonii biofilm

Area of Science:

• Microbiology
• Oral Health
• Bacterial Physiology

Background:

• Streptococcus gordonii is a common oral bacterium.
• Biofilm formation is crucial for bacterial survival and pathogenesis in the oral cavity.
• Understanding S. gordonii biofilm development is key to managing oral health.

Purpose of the Study:

• To develop a 30-day model for S. gordonii colonization on smooth surfaces, incorporating oral nutrient flux.
• To characterize the biphasic expansion of adherent bacterial populations and biofilm architecture.
• To investigate the influence of simple sugars and gene expression changes during biofilm formation.

Main Methods:

• Development of a novel in vitro colonization model simulating oral conditions.
• Observation of bacterial population expansion and biofilm morphology.
• Quantification of gene expression using real-time PCR.

Main Results:

• A biphasic growth pattern was observed during S. gordonii colonization.
• Simple sugars (sucrose, glucose, fructose) significantly influenced biofilm formation.
• Morphological changes correlated with significant shifts in gene expression, with most genes downregulated in the biofilm phase.
• Upregulated genes in the biofilm state were associated with environmental sensing and signaling.

Conclusions:

• The developed model effectively simulates protracted S. gordonii colonization and biofilm development.
• Nutrient availability, particularly simple sugars, plays a critical role in S. gordonii biofilm formation.
• Gene expression analysis reveals adaptive regulatory mechanisms, including environmental sensing, during biofilm maturation.