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Mechanisms underlying interactions between two abundant oral commensal bacteria
Dasith Perera1, Anthony McLean2, Viviana Morillo-López2
1The University of Rhode Island, Kingston, RI, 02881, USA.
The ISME Journal
|November 4, 2021
Summary
Interactions between Haemophilus parainfluenzae and Streptococcus mitis in healthy oral biofilms are influenced by hydrogen peroxide (H2O2) and nutrient exchange. These microbial interactions promote the survival of key species within the human mouth.
Area of Science:
- Microbiology
- Oral Health
- Microbial Ecology
Background:
- Complex polymicrobial biofilm communities are prevalent in the human oral cavity, influencing health.
- Interactions within healthy oral plaque communities are less understood than those during disease.
Purpose of the Study:
- To investigate the interactions between Haemophilus parainfluenzae and Streptococcus mitis, two abundant species in healthy oral plaque.
- To elucidate the mechanisms driving their co-occurrence and mutualistic relationship.
Main Methods:
- In vitro coculture experiments and ex vivo microscopy.
- Analysis of H2O2 production and utilization.
- Investigation of nutrient exchange (NAD) and carbon utilization patterns.
Main Results:
- H. parainfluenzae and S. mitis exhibit density-dependent co-occurrence influenced by H2O2.
- H. parainfluenzae possesses a robust H2O2 resistance system that benefits S. mitis.
- S. mitis likely serves as the in vivo source of NAD for H. parainfluenzae, impacting its carbon metabolism.
Conclusions:
- Mechanistic interactions between H. parainfluenzae and S. mitis contribute to their survival in healthy supragingival plaque.
- These findings provide insights into the dynamics of a healthy oral microbiome.
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