Probiotics S. salivarius K12 and S. salivarius M18 Strengthen Oral Health


The mouth is colonized by 200 to 300 bacterial species, but only a limited number of these species participate in dental decay (caries) or periodontal disease.   An imbalance of good bacteria and bad bacteria in the mouth is considered dysbiosis in the mouth and is thought to be an important cause of periodontal disease and dental decay.

Dental decay is due to the irreversible solubilization of tooth mineral by acid produced by certain bacteria that adhere to the tooth surface in bacterial communities known as dental plaque.

The main bad bacteria associated with dental decay is Streptococcus mutans.  1 

A number of other types of bacteria, such as Actinomyces viscosus and A. naeslundii, live in the mouth, where they are part of a sticky substance called plaque.

Image result for Streptococcus mutans

Streptococcus mutans strain

Streptococcus mutans is the primary causal agent and the pathogenic species responsible for dental caries (tooth decay or cavities) specifically in the initiation and development stages.  2

Advanced periodontal disease has been linked to many chronic diseases, including:

  • Cardiovascular disease
  • Type 2 diabetes
  • Cognitive decline and Alzheimer’s disease
  • Cancer
  • Autoimmune diseases
  • Chronic kidney disease
  • Osteoporosis

Researchers have investigated the potential of probiotics to restore the good bacterial in the oral cavity.  These particular probiotic strains displace the bad bacteria, thus eliminating dysbiosis and restoring the healthy oral flora.

Certain Probiotics Strengthen Oral Health

A number of research studies have shown that two specific strains of Streptococcus salivarius, that are normally found in the mouth, may improve oral health.  These two strains are:

  • Streptococcus salivarius (S. salivarius) strain M18  (BLIS M18)
  • Streptococcus salivarius (S. salivarius) strain K12  (BLIS K12)

These two strains specifically reduce cariogenic and periodontal pathogen levels in the mouth.  This is accomplished by antimicrobial agents that the strains produce and are termed bactericon-like-inhibitory substances (BLIS), otherwise known as lantibiotics.  There are three types of BLIS that the two strains produce in the oral cavity:

  • Salivaricin A
  • Salivaricin B
  • Salivaricin 9

Streptococcus salivarius (S. salivarius) strain K12 is a potent BLIS producer, specifically Salivaricin A (bacteriostatic) and Salivaricin B (bactericidal). 

Both strains are able to produce BLIS antimicrobials in the mouth, however, BLIS K12 is more targeted to ear, nose, throat and immune health while BLIS M18 primarily supports dental health.

Streptococcus salivarius (S. salivarius) strain M18  (BLIS M18) 

Unfortunately only about two percent of the global population has the Streptococcus salivarius necessary to make the M18 peptides.  This small populace comprise people who rarely experience plaque or tooth decay.

Streptococcus salivarius (S. salivarius) strain M18 (BLIS M18) has the ability to break up plaque and neutralize acid that harms teeth and gums.  BLIS M18 produces two unique enzymes that contribute to support for dental health:

  • Urease – neutralizes that lactic acid that is produced the oral cavity by S. mutans.  3
  • Dextranase –  breaks down plaque biofilms caused by S. mutans and inhibits the development of dextrans or extracellular polysaccharides  4

BLIS M18 also corrects and maintains the oral cavity pH.  A more acidic pH oral cavity can lead to tooth demineralization.

BLIS M18 is a potent producer of BLIS or lantibiotics, which destroy disease causing bacteria in the oral cavity.  5  6

A recent study from January 2015 published in the International Journal of Pharma and Bio Sciences showed that M18 probiotic lozenges were efficacious in reducing both moderate to severe gingivitis and moderate periodontitis.  7 

Twenty eight subjects, of both sexes, were selected and divided into 4 groups (2 test groups and 2 control groups).  All 28 subjects had severe gingivitis and moderate periodontitis.  For 30 days, the Test subjects were given a M18 lozenge and the Control group did not receive a lozenge.  Clinical parameters such as plaque index, gingival index, modified sulcular bleeding index and probing pocket depth were recorded and assessed at baseline, day 15, 30, 45 and day 60.

The Test group showed significant reduction in all parameters when compared to that of Control group. After stopping probiotic administration on day 30, the test group showed a significant increase in all the clinical parameters except probing pocket depth on day 45 and day 60.

The Test subjects saw improvement in three areas:

  • less plaque
  • better gingival health
  • less bleeding on probing

Specifically, for the Test subjects, the results were promising in improving all four of these commonly used assessments of periodontal health:

  • The plaque index score decreased 44% by day 30
  • The gingival index score decreased 42% by day 30
  • The sulcular bleeding index score decreased 53% by day 30
  • The probing pocket depth decreased 20% by day 30

Even after 30 days after stopping the lozenges, the Test subjects showed good scores on the 4 indices.  This indicates that M18 has the ability to colonize the oral cavity after using the lozenges.

Streptococcus salivarius (S. salivarius) strain K12 (BLIS K12)  8

Streptococcus salivarius K12 is a strain isolated from the throat of a New Zealand child (who had evidence of exceptional throat health for several years), and is capable of producing two distinct lantibiotics bacteriocins:  9

  • salivaricin A2
  • salivaricin B

The K12 strain is not only effective against S. pyogenes but also inhibits the growth of pathogens such as:

  • Haemophilus influenzae
  • S. pneumoniae
  • Moraxella catarrhalis

These four pathogens are responsible for almost all bacterial pharyngotonsillitis cases in children and adults.  10 

BLIS K12 is a probiotic primarily used for the oral cavity (mouth) and upper respiratory tract and has now been clinically documented to reduce the incidence of strep throat infections in both adults and children.

Streptococcus salivarius: the probiotic for all ages. Diseases that may be alleviated by Streptococcus salivarius probiotics and the ages at which they generally tend to manifest.  (Source:  Developing Oral Probiotics From Streptococcus salivarius)

BLIS K12 attaches to cells in the oral cavity and colonizes the oral cavity and crowds out the bad bacteria.  This effect equalizes the flora in the oral cavity and allows room for the good bacteria to thrive.

Advantages of BLIS K12:

  • Helps maintain mouth and throat health
  • Helps maintain upper respiratory tract health
  • Naturally supports breath freshness