Probiotic Applications of Streptococcus salivarius in Oropharyngeal Health

Streptococcus salivarius is a prominent commensal of the human oral cavity and oropharynx, recognised for its ability to adhere to mucosal surfaces and establish a stable niche. Select strains, notably K12 and M18, produce specific bacteriocins known as salivaricins that inhibit pathogens such as Streptococcus pyogenes and common respiratory bacteria. Beyond direct antagonism, S. salivarius modulates the local microbiome through competitive exclusion, supports mucosal immune function by enhancing salivary immunoglobulin A secretion and influences epithelial barrier integrity. Clinical formulations—lozenges, powders and oropharyngeal sprays—have been developed to deliver these probiotics to diverse populations, including athletes, children and immunocompromised patients. Emerging work on extracellular vesicles suggests that cell-free derivatives may retain immunomodulatory and antimicrobial properties, opening avenues for novel, non-viable probiotic therapies. Collectively, research underscores the global significance of S. salivarius in preventing oropharyngeal infections, reducing antibiotic reliance and improving quality of life through cost-effective, well-tolerated interventions.

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Probiotic Applications of Streptococcus salivarius in Oropharyngeal Health publication trend

The graph below shows the total number of articles in probiotic applications of streptococcus salivarius in oropharyngeal health across all publications each year (not limited to Nature Index journals).

Technical terms

Probiotic: Live microorganisms which, when administered in adequate amounts, confer a health benefit on the host.

Salivaricins: Bacteriocin peptides produced by S. salivarius that inhibit the growth of pathogenic bacteria in the oropharynx.

Extracellular vesicles (EVs): Nano-sized, membrane-bound particles released by bacteria containing proteins and signalling molecules with immunomodulatory potential.

Salivary immunoglobulin A (sIgA): The predominant antibody in saliva that provides frontline mucosal immunity against ingested and inhaled pathogens.

References

1. Use of Streptococcus salivarius K12 in supporting the mucosal immune function of active young subjects: A randomised double-blind study. Frontiers in Immunology (2023).
2. Efficacy of Streptococcus salivarius Blis K12 in the Prevention of Upper Respiratory Tract Infections in Physically Active Individuals: A Randomized Controlled Trial. Microorganisms (2024).
3. Isolation and Characteristics of Extracellular Vesicles Produced by Probiotics: Yeast Saccharomyces boulardii CNCM I-745 and Bacterium Streptococcus salivarius K12. Probiotics and Antimicrobial Proteins (2023).
4. Persistence of the Oral Probiotic Streptococcus salivarius M18 Is Dose Dependent and Megaplasmid Transfer Can Augment Their Bacteriocin Production and Adhesion Characteristics. PLOS ONE (2013).