Preventing recurrent strep throat in children with Streptococcus salivarius eK12 probiotic

Study to Investigate the Prophylactic Effect of Probiotic Streptococcus Salivarius eK12 Supplementation Against Recurrent Streptococcus Pyogenes (GAS) Bacterial Pharyngotonsillitis in Children: A Randomized, Double-blind Controlled Clinical Trial

Not applicable Interventional Liaquat University of Medical & Health Sciences · NCT06370208

This will try a daily probiotic lozenge (Bactoblis® EVOL containing S. salivarius eK12) to prevent repeat strep throat in children aged 3–10 who get frequent infections.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment60 (estimated)
Ages3 Years to 10 Years
SexAll
SponsorLiaquat University of Medical & Health Sciences Academic / other
Locations1 site (Jamshoro)
Trial IDNCT06370208 on ClinicalTrials.gov

What this trial studies

Children aged 3–10 with a recent history of recurrent group A streptococcal pharyngotonsillitis will receive daily S. salivarius eK12 (Bactoblis® EVOL) and be followed at Liaquat University of Medical & Health Sciences. Infections will be confirmed using clinical McIsaac scoring and rapid throat swab testing, and investigators will record the frequency and severity of strep throat episodes and antibiotic courses. Safety and tolerability of the probiotic will be monitored and any adverse events documented. Outcomes will be compared to participants' recent infection history to determine whether the probiotic reduces recurrence.

Who should consider this trial

Good fit: Children aged 3–10 with documented recurrent Streptococcus pyogenes pharyngotonsillitis (≥2 episodes in 6 months or ≥4 in 12 months confirmed by McIsaac score plus rapid antigen test), whose parent/guardian provides consent and who can attend follow-up visits.

Not a fit: Children with severe immune or gastrointestinal disorders, known allergy to probiotics, recent antibiotic use, recent use of oral colonizing probiotics, or those without documented recurrent GAS infections are unlikely to benefit.

Why it matters

Potential benefit: If successful, the probiotic could reduce the number and severity of strep throat episodes in children and lower the need for repeated antibiotic treatments.

How similar studies have performed: Earlier studies with S. salivarius K12 have shown some preventive effects against throat infections, but the re-engineered eK12 strain is newer and has limited published clinical evidence so far.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Children aged 3-10 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.

Where this trial is running

Jamshoro

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Streptococcus Pyogenes Pharyngotonsillitis
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.