Microbial Dynamics in Dental Caries Pathogenesis

The pathogenesis of dental caries emerges from complex microbial communities that colonise the tooth surface and metabolise dietary sugars into organic acids. This polymicrobial biofilm comprises bacteria, fungi and extracellular polymeric substances that orchestrate shifts from health to disease. Streptococcus mutans remains a keystone acidogen, but recent work reveals that less studied taxa, such as Selenomonas sputigena and cross-kingdom partners like Candida albicans, cooperate to shape biofilm architecture and virulence. Heterogeneous microenvironments within the matrix, characterised by acidic micro-niches, drive enamel demineralisation and favour aciduric species, further reinforcing dysbiosis. Key enzymes, notably glucansucrases, synthesise water-insoluble α-glucans that scaffold the exopolysaccharide matrix, while cell wall mannans mediate strong binding interactions. Emerging insights highlight spatial organisation at micron scales, with multicellular superstructures amplifying acid production and resisting mechanical and chemical disruption. Novel strategies targeting biofilm integrity, including catalytic nanoparticles with peroxidase-like activity, offer promising avenues for preventing lesion formation without perturbing the broader oral microbiome. Understanding these dynamic interspecies interactions and matrix assembly mechanisms underpins the development of precision therapeutics for a globally prevalent and costly disease.

Research from Nature Portfolio

Recent studies have demonstrated that Selenomonas sputigena acts as a collaborative pathobiont with Streptococcus mutans, becoming entrapped within streptococcal exoglucans to form a honeycomb-like multicellular superstructure that enhances collective acidogenesis and exacerbates enamel demineralisation in vivo. Another line of enquiry has elucidated how microbial-derived reactive nanoparticles can disrupt biofilm integrity: ferumoxytol nanoparticles bind within the extracellular matrix and catalyse hydrogen peroxide into free radicals, leading to matrix degradation, bacterial death and prevention of caries development in rodent models, while preserving commensal microbial diversity. Foundational research on cross-kingdom biofilm metabolites further reveals that conditioned media from Candida albicans-S. mutans associations contain farnesol and organic acids that upregulate glucosyltransferase expression, promoting Gtf-mediated glucan synthesis and enlarged microcolony formation. Collectively, these findings underscore the importance of spatial microbial interactions and novel anti-biofilm modalities.

Microbial Dynamics in Dental Caries Pathogenesis publication trend

The graph below shows the total number of articles in microbial dynamics in dental caries pathogenesis across all publications each year (not limited to Nature Index journals).

Technical terms

Biofilm: A structured community of microorganisms enmeshed in an extracellular polymeric matrix on a surface.

Pathobiont: A normally harmless microbe that can contribute to disease under certain environmental conditions.

Dysbiosis: An imbalance in microbial community composition associated with disease states.

Exopolysaccharides (EPS): High-molecular-weight polymers secreted by microbes that form the biofilm matrix.

Glucansucrases: Microbial enzymes that synthesise α-glucan polymers from sucrose to build structural glucans.

α-Glucans: Polysaccharides composed of glucose units linked predominantly by α-glycosidic bonds, essential for biofilm matrix scaffolding.

Cross-kingdom interaction: Cooperative or competitive relationships between organisms from different biological kingdoms, such as bacteria and fungi.

References

1. Selenomonas sputigena acts as a pathobiont mediating spatial structure and biofilm virulence in early childhood caries. Nature Communications (2023).
2. Addition of cariogenic pathogens to complex oral microflora drives significant changes in biofilm compositions and functionalities. Microbiome (2023).
3. Detailed structural characterization of five water-insoluble α-glucans produced by glucansucrases from Streptococcus spp.. Carbohydrate Polymers (2024).
4. The Exopolysaccharide Matrix Modulates the Interaction between 3D Architecture and Virulence of a Mixed-Species Oral Biofilm. PLOS Pathogens (2012).
5. Candida albicans stimulates Streptococcus mutans microcolony development via cross-kingdom biofilm-derived metabolites. Scientific Reports (2017).
6. Candida albicans mannans mediate Streptococcus mutans exoenzyme GtfB binding to modulate cross-kingdom biofilm development in vivo. PLOS Pathogens (2017).
7. Topical ferumoxytol nanoparticles disrupt biofilms and prevent tooth decay in vivo via intrinsic catalytic activity. Nature Communications (2018).