Competitive exclusion of pathogenic oral bacteria by probiotics

Competitive exclusion of pathogenic oral bacteria by probiotics refers to the process whereby beneficial oral microbes (probiotics, such as *Lactobacillus plantarum*, *L. salivarius*, *S. salivarius*, and *Bifidobacterium*) suppress or outcompete pathogenic bacteria (e.g., *Streptococcus mutans*, *Porphyromonas gingivalis*, *Fusobacterium nucleatum*) in the oral cavity. This suppression is achieved through several mechanisms: competition for adhesion sites and nutrients, production of antimicrobial metabolites (such as acids, hydrogen peroxide, and bacteriocins), and formation of probiotic biofilms that prevent colonization of harmful bacteria. Some strains can modulate host immune responses or directly downregulate pathogenicity genes in harmful bacteria. This strategy aims to maintain oral microbiome balance, prevent dental caries and periodontal disease, and potentially aid in the prevention of oral cancer by restoring homeostasis and reducing chronic oral inflammation.

Other names

Competitive exclusion (by probiotics)Colonization resistance (in oral cavity)Oral microbiome modulation

Competitive exclusion: probiotics compete for binding/adhesion sites and nutrients. Production of antimicrobial substances (acids, bacteriocins, hydrogen peroxide) suppresses pathogen growth. Biofilm formation by probiotics fills niches to prevent colonization by pathogens. Downregulation of pathogen virulence genes and inhibition of biofilm-associated gene expression. Local or systemic immunomodulation to reduce oral inflammation.