Randomized controlled trial of a postbiotic’s ability to affect microbiome diversity and composition

INTERVENTION: Patients are asked to take one capsule per day of PBPGP22 or a placebo alongside their prescribed antibiotic for approximately 20 days (variability arises because the intervention is given alongside a prescribed antibiotic treatment which may vary in length, intervention from the first day of the antibiotic course and until 10 days after course of antibiotics is completed). Patients are asked to take stool samples on 5 days relative to their scheduled final day of taking the antibiotic: on their final day of taking antibiotics, the following 3 days, and on day 10 after finishing the antibiotic course. The study kit thus contains five stool sample kits with instructions, 30 GP‐22 capsules or 30 placebo capsules (gelatin containing microcrystalline cellulose, identical in appearance). In addition, patients also take a daily capsule of an OTC probiotic during the trial which is included in the study kit. The study kit is barcoded but otherwise unmarked. Study kits were randomized at assembly: a random number was drawn by a computer program to assign treatment (T) or control (C). An eligible patient who is prescribed an oral antibiotic is asked to participate by the doctor on site. If a patient chooses to participate, a staff member of the clinic or a company representative chooses an unmarked box (the study kit). The staff member or the company representative will not know the treatment arm during the handover of the study kit. Patients send their samples by post or hand over the samples in person at the study site. Samples are submitted to a research partner for DNA sequencing. The bar codes will allow the sponsor to identify the treatment arm at the end of the trial. Statistical analyses CONDITION: Gut microbiome diversity loss in patients who receive antibiotics ; Not Applicable PRIMARY OUTCOME: Bacterial alpha diversity measured by 16S rRNA gene sequencing of DNA in stool samples collected at three timepoints relative to the antibiotic treatment course and quantified by the inverse Simpson diversity index: on the final day of antibiotics, the first day after completing the antibiotics course, and the second day after completing the antibiotics course INCLUSION CRITERIA: 1. Otherwise healthy adults with a body mass index (BMI) (18‐28 kg/m²) 2. Patients prescribed a course of antibiotics for 5 days or longer 3. Patients have not had another course of antibiotics in the past 6 months 4. Patients are willing to cease taking any other supplements or probiotics SECONDARY OUTCOME: ; 1. Bacterial alpha diversity measured by 16S rRNA gene sequencing of DNA in stool samples collected at three timepoints relative to the antibiotic treatment course and quantified by the Shannon diversity index: on the final day of antibiotics, the first day after completing the antibiotics course, and the second day after completing the antibiotics course; 2. Bacterial alpha diversity measured by 16S rRNA gene sequencing of DNA in stool samples collected at two timepoints relative to the antibiotic treatment course and quantified by the inverse Simpson diversity index: on the third and tenth day after completing the antibiotics course; 3. Blood inflammation markers measured using C‐reactive protein test at the end of antibiotic treatment course;