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The University of Southampton
Primary Care Research Centre

The BLIS study

The BLIS study: a feasibility study assessing compliance, acceptability and colonisation with different dosing regimens of the probiotic supplement Streptococcus salivarius K12 (Bactoblis®) in adults.

BLIS logo

Sore throat due to infection of the throat or tonsils (tonsillitis) is a very common reason for people visit their GP. Many will receive antibiotics, however antibiotic resistance is becoming a major problem, and we need to find ways to prevent sore throat or tonsillitis without using antibiotics.

Recent studies have shown that a probiotic supplement called S. salivarius K12 (Bactoblis®), containing ‘good’ bacteria may be able to prevent tonsillitis. These probiotic supplements have been tested in many studies (involving over 2400 children and adults), and all these studies have shown that they are safe.

Bactoblis® is now able to be bought commercially in many countries, and we would like to find out how effectively the probiotics work and the best dose to take in order to prevent tonsillitis. These results will help us design a large clinical trial in the future, to test how effective it is at preventing tonsillitis.

About the study

The project is being done entirely remotely, and we are looking for adults to take part if they have had two or more episodes of sore throat or tonsillitis in the past three years. It will involve one short video call with the study team. Participants will then be asked to take probiotic lozenges once nightly for a maximum of two weeks, and take mouth swabs on days 1, 2, 7, 14, 21, and 35 (returned via post). They will also be asked to complete two very short online questionnaires on days 14 and 35. Participants will be compensated up to £45 in amazon vouchers for the inconvenience caused.


The research has received funding from the University of Southampton Biomedical Research Centre, Southern Health, and Bluestone Pharma. The study is sponsored by the University of Southampton, and is being conducted by the Primary Care Research Centre and the Southampton NIHR Clinical Research Facility.

Contact details:

Those interested in taking part should contact the study team at:

Or call 023 8120 4989.

Chief investigator

Professor Paul Little

Co-Principal Investigator

Dr Christopher Wilcox

Dr Merlin Willcox


Professor Nick Francis

Professor Michael Moore

Dr Taeko Becque

Dr Mark Lown

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