Prophylactic Effect of Probiotic Streptococcus Salivarius eK12 Against Recurrent Streptococcus Pyogenes Pharyngotonsillitis Infection in Pediatrics

August 20, 2026 updated by: Dr. Amjad Khan, Liaquat University of Medical & Health Sciences

Study to Investigate the Prophylactic Effect of Streptococcus Salivarius eK12 Against Recurrent Group A Streptococcal Pharyngotonsillitis in Children: A Randomized, Double-Blind, Parallel-Group Controlled Trial

Recurrent Group A Streptococcus (GAS) infections, primarily presenting as strep throat, are a significant health concern in pediatric populations, leading to symptoms like sore throat, fever, and swollen lymph nodes. GAS is highly contagious and can spread easily among children in close-contact environments like schools and daycare centers, often resulting in frequent re-infections. Managing these recurrent infections typically requires antibiotics, but reliance on antibiotics carries risks, including resistance development, gut microbiota disruption, and various side effects. Probiotic therapy, particularly with Streptococcus salivarius K12, has shown promise as a preventive approach, utilizing competitive exclusion and antimicrobial production to inhibit GAS growth in the oral cavity. Recent studies have advanced this with the development of S. salivarius eK12, a re-engineered strain that enhances efficacy against GAS by preventing the survival-promoting interactions between the probiotic and pathogenic bacteria. This modified strain, now registered as Bactoblis® EVOL in Italy (EU), holds potential as an effective version to reduce the incidence and severity of GAS infections without the drawbacks of antibiotic therapy.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

The primary aim of this clinical trial is to evaluate whether prophylactic use of S. salivarius eK12 can effectively reduce the frequency of strep throat episodes in children. By assessing the efficacy of S. salivarius eK12 supplementation, this study seeks to provide insights into its potential as a non-antibiotic preventive strategy for recurrent strep throat infections in pediatric populations.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
82

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Pakistan
    • Balouchistan
      • Quetta, Balouchistan, Pakistan, 87300
        • Saboor Clinic
    • Khyber Pakhtunkhwa
      • Haripur, Khyber Pakhtunkhwa, Pakistan, 22620
        • Dr. Khan Afsar ENT Clinic
    • Sindh
      • Hyderābād, Sindh, Pakistan, 71000
        • CDF Hospital (Bilawal Medical College, LUMHS)
      • Hyderābād, Sindh, Pakistan, 71500
        • Dr. Allah Wadhayo Kallo Clinic (Shifa Hurmat Diagnostic and Research Centre)

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Child

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Children aged 3-11 years.
  • Recent history of documented recurrent episodes of Streptococcus pyogenes pharyngo- tonsillitis infection in the last 6 months, or 4 or more episodes in the last 12 months (S.

pyogenes infection being defined as: McIsaac score with clinical score ≥ 2 plus confirmation of S. pyogenes presence with rapid throat swab (RAD) method or McIsaac score =5.

  • Willingness to comply with the study protocol and attend scheduled follow-up visits.
  • Written informed consent obtained from the parent or legal guardian.

Exclusion Criteria:

  • Children with known allergies or hypersensitivity to probiotics or any components of the study product.
  • Current use of antibiotics or within the past 30 days.
  • Used oral colonizing probiotics in the last 6 months.
  • Presence of severe underlying medical conditions affecting the immune system or gastrointestinal tract.
  • Participation in other clinical trials involving investigational drugs or interventions.
  • Inability to adhere to the study requirements due to logistical or social reasons.
  • History of rheumatic disorders, bronchospasm, severe asthma, or allergy requiring corticosteroids.
  • Past tonsillectomy or an indication for adeno-tonsillectomy; or severe respiratory or systemic disorders
  • Individuals immunocompromised or had a condition favouring recurrent Acute Otitis Media (AOM), including severe atopy, acquired or congenital immunodeficiency, cleft palate, craniofacial abnormalities, obstructive adenoids, a chronically ruptured eardrum, sleep apnoea, or tympanostomy tubes
  • Children undergoing current pharmacological therapies to prevent recurrent respiratory infections.
  • Any other medical condition or circumstance that, in the investigator's judgment, would compromise the safety of the participant or the integrity of the study.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Probiotic supplement group
Participants in this group will receive probiotic Streptococcus salivarius eK12 (Bactoblis® EVOL containing ca. 1 billion CFU of Streptococcus salivarius eK12/capsule) as daily one orally dissolving tablet (to be slowly dissolved in the mouth before sleeping at night time), plus 200 IU vit D3 (one tablet) for 3-months.
Dietary supplement: Probiotic Bactoblis® EVOL (Streptococcus salivarius eK12)
Bactoblis® EVOL: containing one billion CFU of probiotic Streptococcus salivarius eK12
Dietary supplement: Oral vit D3
Oral vit D3 tablets (200 IU)
Active Comparator: Control group
Participants in this group will receive only 200 IU vit D3 as daily two orally dissolving tablets under the same dosing regimen.
Dietary supplement: Oral vit D3
Oral vit D3 tablets (200 IU)

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Recurrence of Streptococcus pyogenes pharyngotonsillitis infection
Time Frame: 6-months
Number of episodes of Streptococcus pyogenes pharyngotonsillitis infection
6-months

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Protection against viral infection
Time Frame: 6-months
Number of incidences of viral throat infection
6-months
Protection against Acute Otitis Media infection
Time Frame: 6-months
Number of incidences of Acute Otitis Media infection
6-months
Protection against respiratory infection
Time Frame: 6-months
Number of incidences of Tracheitis infection
6-months
Protection against Rhinitis
Time Frame: 6-months
Number of incidences of Rhinitis
6-months
Protection against flu
Time Frame: 6-months
Number of incidences of flu
6-months
Protection against Enteritis
Time Frame: 6-months
Number of incidences of Enteritis infection
6-months
Protection against Stomatitis
Time Frame: 6-months
Number of incidences of Stomatitis infection
6-months
Severity of Group A Streptococcal (GAS) Symptoms
Time Frame: 6-months
Severity of GAS-associated symptoms assessed using a 10-point Visual Analogue Scale (VAS)
6-months
Use of Antibiotics
Time Frame: 6-months
Number of antibiotic courses prescribed during the 6-month study period.
6-months
Persistence of Streptococcus salivarius eK12 in saliva after washout
Time Frame: Month 6, approximately 3 months after discontinuation of eK12 supplementation.
Post hoc exploratory ancillary analysis, conceived after study completion and unblinding, evaluating the presence of the administered Streptococcus salivarius eK12 strain in saliva at the end of the 6-month study period, approximately 3 months after discontinuation of eK12 supplementation. Saliva samples will be examined using a strain-specific microbiological or molecular method capable of distinguishing eK12 from the parental K12 strain. The outcome will be reported as the proportion of participants with detectable eK12 and, if a validated quantitative method is used, the salivary abundance of eK12. This analysis was not a prespecified outcome of the original clinical trial.
Month 6, approximately 3 months after discontinuation of eK12 supplementation.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Liaquat University of Medical & Health Sciences

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Università degli Studi dell'Insubria

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
December 1, 2025

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
July 31, 2026

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
July 31, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
April 13, 2024

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 13, 2024

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
April 17, 2024

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
August 21, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 20, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
August 1, 2026

More Information

Terms related to this study

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • LUMHS/REC/-496/11.11.2024

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Deidentified individual participant data underlying the results reported in the published article, together with the corresponding data dictionary.

IPD Sharing Time Frame

Beginning 3 months and ending 5 years after publication of the article.

IPD Sharing Access Criteria

Data will be made available to researchers whose methodologically sound proposals are approved by the study investigators, for the purposes specified in the approved proposal and after execution of a data-use agreement. Requests should be directed to the corresponding author at pchiarmaria@gmail.com.

IPD Sharing Supporting Information Type

  • SAP

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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