The Predominant Oral Microbiota Is Acquired Early in an Organized Pattern

Area of Science:

• Microbiology
• Human Microbiome
• Developmental Biology

Background:

• The human oral cavity is initially sterile, and the processes governing early microbial community assembly remain poorly understood.
• Understanding oral microbiome development is crucial for insights into infant health and disease susceptibility.

Purpose of the Study:

• To investigate the acquisition and assembly dynamics of the oral bacterial microbiome in infants during their first year of life.
• To identify factors influencing oral microbial community complexity and structure over time.

Main Methods:

• Collection of oral samples from nine infants and their mothers.
• Analysis of bacterial community composition using 16S rRNA gene sequencing.

Main Results:

• Initial colonization by exogenous skin and environmental bacteria was rapidly replaced by a shared core oral microbiome.
• Ordered microbial succession led to increasingly complex communities, converging to a similar profile among infants by one year.
• Introduction of diverse nutrients, rather than tooth eruption, correlated with increased microbial complexity.
• Infants harbored fewer species than mothers, primarily due to a lack of certain anaerobes, indicating ongoing development.

Conclusions:

• The dominant structure of the infant oral microbiome is established early and appears to be persistent.
• Dietary factors play a significant role in shaping the complexity of the oral microbiome during early development.
• Oral microbiome acquisition and assembly continue beyond infancy, with implications for long-term oral health.