To investigate whether probiotic supplementation during the consumption of oral antibiotics can impact gastrointestinal responses and/or the regrowth of the gut microbiota.

The human gut (gastrointestinal tract) is home to more than a trillion mostly "friendly bacteria" = the gut microbiota - that support the well-being and health of an individual through a variety of mechanisms. Antibiotic treatment impacts on the microbiota and reduces the overall numbers and diversity which causes metabolic shifts and increases susceptibility to colonization by potentially pathogenic and/or resistant bacteria and thereby increases the risk of bacterial antibiotic resistance. This trial aims to investigate whether probiotic supplementation during the consumption of oral antibiotics can impact the gastrointestinal responses and/or the composition/functionality of the regrowth of the gut microbiota.

The trial will be a double blinded, placebo-controlled study consisting of 50 participants (25 per group), aged 18-65, to be enrolled after being prescribed a 5 to 10-day course of antibiotics. The study will be randomized through an independent statistician.

The study will involve three site visits, the first visit occurs at enrolment when the participant is randomised and measures of height, body weight and blood pressure are taken. The participants will also answer a quality of life questionnaire at visit 1 and will receive the study intervention. A stool sample will be collected at this visit (if possible) and the participant will be given two more stool sample collection kits, a gastrointestinal tract symptom record sheet too b completed daily throughout the study and a bowel habit diary to be completed per defecation..

The second visit will take place the day after the completion of the prescribed antibiotic course and at this visit participants will return a stool sample collected at home the previous day, and asked to complete another quality of life questionnaire. The final visit will take place at around day 30, when again they will return a stool sample collected within 48 hours of the visit, return all gastrointestinal symptom record sheets and bowel habit diaries as well as returning any unused intervention (for compliance monitoring). Scientists will use the information and samples collected to determine if there was any benefit to taking the probiotic supplement.

It is considered that the daily intake of the probiotics will improve general wellbeing and mental health. Due to the chance that the participant may receive the placebo, it is perceived that these benefits will be confined to the participants who are randomly assigned the intervention. Participation in the study will bring more information and will improve our understanding of the benefits of daily probiotic supplementation.

There have been no adverse reactions associated with the regular consumption of this probiotic product but participants may experience mild side effects such as a change in bowel habit and/ or increased flatulence (intestinal gas) during the first few days of taking the supplement.

Inclusion Criteria:

1. Male or female, aged 18-65
2. Receiving a 5 to 10 day course of oral antibiotics
3. Willing to provide 3 faecal samples over the duration of the study
4. Willing to refrain from taking non-GP (general practitioner) prescribed antibiotics

Exclusion Criteria:

1. Consumed regular probiotic supplementation within the last 1 month prior to the study
2. Consumed any antibiotic within the last 3 months
3. Prescribed antibiotics for a gastrointestinal related issue
4. Diagnosed with diabetes
5. Are immunodeficient or undergoing immunosuppressive therapy
6. Diagnosed with arrhythmia, ventricular extrasystole, atrioventricular block or other cardiovascular disease deemed as a risk by study doctor
7. Diagnosed with a cardiovascular disease
8. Pregnancy or planning pregnancy
9. Diagnosed with a severe systemic disease e.g. cancer, dementia, advanced organ failure.
10. Unexplained loss of weight in recent months