Genomic and Transcriptomic Adaptation to Chlorhexidine in Streptococcus spp

Area of Science:

• Microbiology and Genomics
• Antimicrobial Resistance Research
• Dental Antiseptics and Public Health

Background:

• Chlorhexidine digluconate (CHX) is a common antiseptic in dentistry.
• The risk of CHX contributing to antimicrobial resistance (AMR) is not fully understood.
• Investigating CHX adaptation mechanisms in oral bacteria is crucial for assessing AMR potential.

Purpose of the Study:

• To explore the genomic and transcriptomic adaptations of Streptococcus species to CHX.
• To identify specific genes and pathways involved in CHX resistance.
• To assess the potential link between CHX use and the development of AMR.

Main Methods:

• Genomic and transcriptomic analyses of three clinical Streptococcus isolates (S. salivarius, S. mitis, S. vestibularis) and their CHX-adapted counterparts.
• Identification of mutations and gene expression changes under CHX exposure.
• Comparative analysis of conserved and species-specific adaptation mechanisms.

Main Results:

• Genomic analysis revealed mutations in genes related to membrane structure, DNA repair, and metabolism, potentially conferring CHX resistance.
• CHX-adapted strains constitutively expressed stress response, DNA repair, and cell surface restructuring genes.
• Species-specific adaptations were observed, including changes in metabolic pathways and transport systems, with S. mitis showing an acute CHX response.

Conclusions:

• CHX adaptation in Streptococcus species is complex, involving both genetic mutations and significant transcriptomic shifts.
• Constitutive expression of stress and resistance-associated genes suggests a pre-adaptation state.
• Findings highlight the need for further investigation into CHX's role in AMR development and clinical implications.