Efflux inhibitor suppresses Streptococcus mutans virulence properties

Area of Science:

• Microbiology
• Bacteriology
• Molecular Biology

Background:

• Efflux pumps are crucial for bacterial pathogenicity.
• Efflux inhibitors (EIs) can suppress bacterial virulence.
• The EI of Streptococcus mutans, a primary cause of dental caries, is largely unknown.

Purpose of the Study:

• To identify an EI in Streptococcus mutans.
• To investigate the impact of the identified EI on S. mutans virulence, cariogenicity, and stress response.

Main Methods:

• Ethidium bromide efflux assay was used to identify the EI.
• Quantitative real-time PCR (qPCR) was employed to analyze gene expression profiles.
• Assays were conducted to assess acid tolerance, mutacin production, transformation efficiency, biofilm architecture, extracellular polysaccharide distribution, and glycosyltransferase activity.

Main Results:

• Reserpine was identified as the EI for S. mutans.
• Reserpine significantly suppressed acid tolerance, mutacin production, and transformation efficiency.
• Reserpine altered biofilm structure, extracellular polysaccharide content, and glycosyltransferase activity, while also modifying virulence and quorum-sensing gene expression.

Conclusions:

• Reserpine effectively suppresses multiple virulence factors in Streptococcus mutans.
• Reserpine shows promise as an adjunct anticariogenic agent for managing dental caries.
• Targeting efflux pumps in S. mutans offers a potential strategy to reduce cariogenicity.