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

Study to Evaluate the Safety and Human Tolerance of the Oral Probiotic Streptococcus Salivarius eK12: A Randomized, Double-blind Clinical Trial

The human oral cavity contains a diverse community of microorganisms essential for oral and overall health. Streptococcus salivarius K12 (eK12) has emerged as a promising oral probiotic due to its natural colonization of the throat and its ability to inhibit pathogens such as Streptococcus pyogenes, a major cause of streptococcal pharyngitis. It supports oral hygiene by producing antimicrobial substances like salivaricins and inhibiting odor-causing bacteria. The engineered eK12 variant (Bactoblis® Evol) has been developed to overcome inactivation by GAS-secreted protease SpeB, thereby enhancing its prophylactic potential against Group A Streptococcus (GAS) colonization.

This clinical study includes a randomized, double-blind, placebo-controlled trial in Pakistan to evaluate the safety and human tolerance of eK12 in healthy adults. To enhance generalizability, an additional open-label cohort of healthy adults in Italy will receive eK12 without a control group.

Study Overview

• Status: Completed
• Conditions: Tolerability; Safety
• Intervention / Treatment: Dietary supplement: Oral probiotic Streptococcus salivarius eK12; Other: Placebo

Detailed Description

The aim of the present clinical study is to evaluate the safety and tolerability of Streptococcus salivarius eK12 in healthy adults. The study consists of a randomized, double-blind, placebo-controlled arm in Pakistan involving 29 participants (allocated 1:1 to eK12 or placebo).

In addition, an open-label cohort of 20 healthy adults will be enrolled in Italy, all of whom will receive eK12, to assess tolerability in a separate population without a control group. This complementary cohort is included to enhance the generalizability of the findings across different populations and to obtain supportive safety data in a real-world setting where the product (commercially available in the EU as Bactoblis® Evol) is already in use.

Through comprehensive assessments and close monitoring of participants, this study will provide critical insights into the safety profile and human tolerance of the probiotic-modified strain. The findings will contribute to the growing body of knowledge needed to support its use in oral health management.

• Study Type: Interventional
• Enrollment (Actual): 29
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Pakistan
  • Hub, Pakistan, 90250
    • Jam Ghulam Qadir Civil Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

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.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Probiotic supplement group; Participants in this arm will daily receive 2 orally dissolving tablets (single administration) of probiotic Streptococcus salivarius eK12 (Bactoblis® EVOL: containing ca. 10 billion CFU of S. salivarius eK12) for 28-days.	Dietary supplement: Oral probiotic Streptococcus salivarius eK12; Bactoblis® EVOL (containing 10 billion CFU of S. salivarius eK12)
Placebo Comparator: Control group; Participants in this arm will daily receive 2 orally dissolving placebo tablets (single administration) for 28-days.	Other: Placebo; Orally dissolving placebo tablets

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Effect on oral health physical condition	Incidence of physical abnormality in pharynx, tongue, teeth, gums and oral mucosa	3-months
Effect on other physical features	Incidence of any physical abnormality in the skin, eyes, ears, nose, throat, and mental health	3-months
Effect on vital signs	Any changes in the heart rate (heart beats per minute (bpm))	3-months
Effect on vital signs	Any changes in the respiratory rate (number of breaths per minute)	3-months
Effect on vital signs	Any changes in the blood pressure (both systolic pressure and diastolic pressure)	3-months
Effect on vital signs	Any changes in the body temperature	3-months
Effect on blood biochemistry	Any changes in the liver function tests (Serum alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase)	3-months
Effect on blood biochemistry	Any changes in the renal function tests (serum creatinine, serum urea, blood urea nitrogen)	3-months
Effect on blood biochemistry	Any changes in the lipid profile tests (serum total cholesterol, serum triglycerides, serum high density lipoprotein-cholesterol, serum low density lipoprotein-cholesterol)	3-months
Effect on blood biochemistry	Any changes in the blood glucose levels	3-months
Effect on blood electrolytes balance	Electrolyte tests (e.g., sodium, potassium, chloride, bicarbonate)	3-months
Effect on hematology	Full blood count	3-months
Incidence of inflammation	C-recative protein (CRP) blood test	3-months
Incidence of gastrointestinal side effects	Abdominal pain, bloating, gastric reflux, nausea, vomiting, diarrhea, and gas or flatulence	3-months
Incidence of Adverse events (AEs)	Any adverse events that may occur during the study period	3-months

Collaborators and Investigators

• Sponsor: Liaquat University of Medical & Health Sciences
• Collaborators: Università degli Studi dell'Insubria

Study record dates

Study Major Dates

• Study Start (Actual): November 1, 2024
• Primary Completion (Actual): August 25, 2025
• Study Completion (Actual): August 25, 2025

Study Registration Dates

• First Submitted: April 14, 2024
• First Submitted That Met QC Criteria: April 18, 2024
• First Posted (Actual): April 23, 2024

Study Record Updates

• Last Update Posted (Estimated): September 5, 2025
• Last Update Submitted That Met QC Criteria: September 3, 2025
• Last Verified: September 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Substandard Drugs; Pharmaceutical Preparations; Counterfeit Drugs
• Other Study ID Numbers: MMC/ERC/03.03.2025

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No