Evaluation of Safety and Human Tolerance of Oral Probiotic Streptococcus Salivarius eK12

The human oral cavity contains a diverse community of microorganisms essential for oral and overall health. Streptococcus salivarius K12, has emerged as a promising oral probiotic due to its natural occurrence in the throat and mucosa, where it competes with pathogens and helps maintain microbial balance. Known for producing antimicrobial substances like salivaricins, S. salivarius K12 protects against common pathogens such as Streptococcus pyogenes, a cause of streptococcal pharyngitis, and supports oral hygiene by inhibiting odor-causing bacteria. S. salivarius K12, registered as a dietary supplement in Italy (EU) under trade name Bactoblis®, has been studied extensively, showing potential in preventing upper respiratory tract infections with a strong safety profile. Recent research has revealed that during co-colonization with group A streptococcus (GAS), S. salivarius K12's antimicrobial activity may be compromised by GAS-secreted protease SpeB. To counteract this, the researchers developed an enhanced (engineered) variant, called S. salivarius eK12, designed to prevent GAS interference, which showed increased effectiveness in preventing GAS colonization in vivo, advancing its potential as a therapeutic probiotic.

The aim of the present clinical study is to validate the safety and tolerability of S. salivarius eK12 in healthy adults. Through comprehensive assessments and close monitoring of participants' responses, this study will provide crucial insights into the probiotic modified strain's safety profile and tolerance in humans. The findings from this study will not only advance our understanding of S. salivarius eK12's safety but also offer valuable guidance for its future use in evidence-based therapeutic applications for oral health management and disease prevention.

Eligibility Criteria:
Inclusion Criteria:

* Adults, both male and female, aged 18 to 60 years.
* Stable health condition with no acute illness at the time of enrollment.
* BMI 18.5-35 kg/m2
* No known food allergies or intolerances to probiotics
* All clinical chemistry, hematology and urinalysis parameters and vital signs (blood pressure, respiratory rate, temperature, heart rate) within clinically acceptable ranges.
* Ability and willingness to provide informed consent.
* Must be willing to comply with study procedures and attend scheduled visits.

Exclusion Criteria:

* Individuals with a history of severe allergies or adverse reactions to probiotics or any of the components of the study product.
* Participants with a recent history of oral surgery or dental procedures within the past 4 weeks.
* Individuals with severe dental problems or undergoing active dental treatment.
* Individuals with a known diagnosis of systemic diseases affecting the oral cavity (e.g., oral cancer, Sjögren's syndrome).
* Individuals with compromised immune systems, or a history of immunodeficiency disorders or undergoing immunosuppressive therapy.
* Pregnant or breastfeeding females.
* Current smokers or individuals who have quit smoking within the past 6 months.
* Individuals currently using antibiotics or have used them within the past 4 weeks.
* Individuals with a history of gastrointestinal disorders (e.g., inflammatory bowel disease, irritable bowel syndrome).
* Individuals with unstable metabolic diseases/disorders, heart failure or a history of endocarditis.
* Frequent user of alcohol or over the counter laxatives, or herbal-based supplements (but not vitamin supplements), or prescription drugs that may potentially influence the biomarkers to be measured in the study.
* Those with any chronic systemic illness that might affect participation in the trial or interpretation of results.
* Participants currently enrolled in another clinical trial involving probiotics or oral health interventions.
* Those unable to adhere to the study protocol or unlikely to complete the study period due to anticipated relocation or other personal reasons.
* Any other condition or circumstances that, in the opinion of the investigator, might compromise the safety of the participant or the validity of the study results.