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Updated: Jun 26, 2026
09:49
Investigation of Microbial Cooperation via Imaging Mass Spectrometry Analysis of Bacterial Colonies Grown on Agar and in Tissue During Infection
Published on: November 18, 2022
Polymicrobial interactions stimulate resistance to host innate immunity through metabolite perception
Matthew M Ramsey1, Marvin Whiteley
1Section of Molecular Genetics and Microbiology, University of Texas, Austin, TX 78712, USA.
Summary
Oral bacteria Aggregatibacter actinomycetemcomitans gain resistance to immune attack when grown with streptococci. This involves sensing hydrogen peroxide, boosting a protein that protects against human serum killing.
Area of Science:
- Microbiology
- Immunology
- Oral Health
Background:
- Oral bacteria form multispecies biofilms with complex interactions.
- These interactions influence individual and community physiology.
- Understanding microbial interactions is crucial for oral health.
Purpose of the Study:
- To investigate how coculture affects the oral pathogen Aggregatibacter actinomycetemcomitans' resistance to host immunity.
- To elucidate the molecular mechanisms underlying this enhanced resistance.
Main Methods:
- Coculture of A. actinomycetemcomitans with streptococci.
- Analysis of gene expression, specifically the complement resistance protein ApiA.
- Investigating the role of the oxidative stress regulator OxyR.
- Testing resistance to killing by human serum.
Main Results:
- A. actinomycetemcomitans exhibits increased resistance to innate immunity during coculture with streptococci.
- Hydrogen peroxide produced by streptococci triggers enhanced ApiA expression in A. actinomycetemcomitans.
- The OxyR regulator is essential for inducing apiA transcription and serum resistance.
- ApiA expression is critical for survival in human serum during coculture.
Conclusions:
- Interactions within polymicrobial communities enhance bacterial resistance to host innate immunity.
- Sensing inter-species metabolites like hydrogen peroxide is a key mechanism for this resistance.
- Understanding these interactions is vital for addressing oral diseases and host-microbe dynamics.
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