MicrobiomePOTATO-2NCT07594860
Effect of a Probiotic or Postbiotic on Gut Microbiome During Antibiotic Treatment
A study testing Probiotic and Postbiotic in people with Microbiome, run by The Archer-Daniels-Midland Company at 1 site in Greece.
Trial summary
This study assesses the effects of a probiotic or postbiotic on gut microbiome during antibiotic treatment. Read more about this study
- Who is it for?
- Ages 18 to 65 yearsHealthy volunteers can take part
- Conditions the study is for
- Microbiome
- What is being tested?
- Probiotic and Postbiotic
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 126 participants
- Where
- 1 siteGreece
- Study dates
- 27 Aug 2026to 31 May 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 65 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Participants meeting ALL of the following criteria will be recruited for the study:
- Males and females aged ≥18 to ≤ 65 years; if female, either not of childbearing potential or using a medically approved method of birth control and willing to take a pregnancy test at screening.
- Body mass index (BMI) 18.5-29.9 kg/m².
- Healthy as determined by medical history and physical examination.
- Agreed not to change current dietary habits during the course of the study.
- Able to attend study visits, comply with study requirements (consumption of study medications, especially biological sample collection procedures, and study visit schedule) and provide reliable and complete data regarding AEs/SAEs and PROs.
- Have been informed and have given written consent for the use of their data in accordance with local regulations before study inclusion.
Who cannot join
- Participants meeting ANY of the following criteria will be excluded from the study:
- Women who are pregnant, breastfeeding, or planning to become pregnant during the course of the study.
- People on vegetarian or vegan diet; People on special diet (e.g. Ducan, Keto, etc.)
- BMI ≥ 30 kg/m² or <18.5 kg/m².
- History of intake of antibiotics, other probiotics, postbiotics, prebiotics, synbiotics, proton pump inhibitors, acid sequestrants (cholestyramine, Bile colestipol), within six months prior to the screening day.
- Participation in other clinical trials in the last 90 days prior to screening.
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- Allergy to any penicillin antibiotic or any other beta-lactam agent (e.g. cephalosporin, carbapenem or monobactam).
- History of jaundice/hepatic impairment due to amoxicillin/clavulanic acid.
- Active smokers or using any form of smokeless tobacco.
- Participants with substance abuse problems (within two years) defined as:
- Use of recreational drugs (such as cocaine, methamphetamine, marijuana, etc.)/ Nicotine dependence.
- High-risk drinking as defined by the consumption of four or more alcohol-containing beverages on any day or eight or more alcohol-containing beverages per week for women and five or more alcohol-containing beverages on any day or 15 or more alcohol-containing beverages per week for men.
- Participants having clinically significant illnesses of cardiovascular, endocrine, immune, respiratory, hepato-biliary, kidney and urinary, haematological, musculoskeletal system and/or any inflammatory disorder, tumour, and other gastrointestinal diseases.
- Participants with a history of bariatric surgery or surgical resection of the stomach, small intestine, or large intestine.
- Participants actively using GLP1 agonist drugs (Wegovy, Semiglutide etc.) or completed treatment with said medication less than 12 weeks before screening.
- Any condition that could, in the opinion of the Investigator, preclude the participant's ability to successfully and safely complete the study or that may confound study outcomes.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Greece1 site, 1 recruiting
- Recruiting
General Hospital of Thessaloniki Papageorgiou
Thessaloniki, 56429
Maria Theodoridou, +30 210 6147282, maria.theodoridou@nextcro.eu
About this study
Official title: Assessment Of Gut Microbiome Changes During Antibiotic Treatment With Probiotic, Postbiotic Or Placebo: A Randomized, Triple-blind, Placebo-controlled Pilot Study.
This study assesses the effects of a probiotic or postbiotic on gut microbiome during antibiotic treatment.
Read the detailed description
The current study aims to assess the changes in microbiome composition in healthy adults receiving antibiotic treatment, and concomitantly a probiotic or postbiotic. The trial will be run in Greece, and will recruit healthy adults from the general population.
- Conditions
- Microbiome
- Being tested
- Probiotic, Postbiotic, Placebo
- Keywords
- Antibiotic, Dysbiosis, Microbiome composition, Antibiotic Resistance Genes, Microbiome Recovery, Antibiotic Scarring, Probiotic, Postbiotic
- Medical subject headings
- Dysbiosis
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
ProbioticDietary supplement
Participants in this arm will receive a daily dose of of a probiotic (live bacterium), in a form of 2 capsules once daily, for 28 days.
PostbioticDietary supplement
Participants in this arm will receive a daily dose of a postbiotic (heat-inactivated bacterium), in a form of 2 capsules once daily, for 28 days.
PlaceboDietary supplement
Participants in this arm will receive an equivalent placebo for the duration of the study (28 days).
| Study group | Role | What they receive |
|---|---|---|
| Probiotic | Experimental | Participants in this arm will receive a daily dose of a daily dose of of a probiotic (live bacterium), in a form of 2 capsules once daily, for 28 days. Receives: Dietary Supplement: Probiotic |
| Postbiotic | Experimental | Participants in this arm will receive a daily dose of a postbiotic (heat-inactivated bacterium), in a form of 2 capsules once daily, for 28 days. Receives: Dietary Supplement: Postbiotic |
| Placebo | Placebo comparator | Participants in this arm will receive an equivalent placebo for the duration of the study (28 days). Receives: Dietary Supplement: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Changes in gut microbiome composition between baseline and day 14 as compared to placebo.
To assess the effects of a probiotic or postbiotic in gut microbiome composition of healthy adults receiving antibiotic therapy, as measured by changes in alpha and beta diversity of the gut microbiome as compared to placebo.
Measured: Day 0 and Day 14
Secondary outcomes (7)
Changes in gut microbiome composition throughout the study as compared to placebo and baseline.
Changes in microbiome composition as measured by changes in alpha and beta diversity of the gut microbiome throughout the study as compared to placebo and baseline.
Measured: Day 0, Day 3, Day 7, Day 28, and Day 56
Changes in abundance of beneficial versus opportunistic/ pathogenic bacterial species throughout the study as compared to baseline and to placebo
Effects of a probiotic or postbiotic on the abundance of beneficial versus opportunistic/pathogenic bacterial species throughout the study as compared to baseline and to placebo.
Measured: Day 0, Day 3, Day 7, Day 14, Day 28, and Day 56
Changes in the abundances of microbial genes contained in specific functional modules through the study as compared to baseline and placebo.
Effects of probiotic or postbiotic on the abundances of genes contained in specific functional modules obtained from KEGG database. A Gene Set Enrichment Analysis (GSEA) is performed to obtain which modules are enriched by the biotics effect thought the study. Significant associations will be reported with the Normalized Enrichment score (NES) and adj.p.value.
Measured: Day 0, Day 7, Day 14, Day 28, and Day 56
Study the associations of specific microbe abundances with the development of gastrointestinal (GI) symptoms
Association between each bacterial abundance and the clinical measures, related to GI symptoms, will be performed using linear models. Significant associations will be reported with the linear model coefficient and adj.p.value.
Measured: Day 0, Day 3, Day 7, and Day 14
.Changes in the abundances of microbial virulence factors and antibiotic resistant genes through the study as compared to baseline and placebo.
Effects of probiotic or postbiotic on the abundances of genes annotated as virulence factors or antibiotic resistant genes through the study as compared to baseline and placebo. The results will be tested using the most fitting statistical method, and p.value will be reported.
Measured: Day 0, Day 7, Day 14, Day 28, and Day 56
Safety profile throughout the study as compared to placebo.
The number of adverse events (AE)/serious adverse events (SAE) related to the study investigational product occurring during the study compared to placebo.
Measured: 56 days
Tolerability of a probiotic or postbiotic as measured by a validated questionnaire and compared to placebo.
Assess tolerability of a probiotic or postbiotic consumption as measured by a validated questionnaire, the Gastrointestinal Symptom Rating Scale (GSRS) throughout the study and compared to baseline and placebo.
Measured: Day 0, Day 7, Day 14, Day 28, and Day 56
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted19 May 2026
- Study start27 Aug 2026
- Primary completion31 May 2027 (estimated)
- Study completion31 May 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for MicrobiomeStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 126 participants (estimated)
Sponsor and investigators
- Lead sponsor
- The Archer-Daniels-Midland Company
- Sponsor type
- Industry (pharma, biotech, devices)
- Collaborators
- NEXT CRO
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07594860
- Sponsor's protocol ID
- CTB2024TN403
- Acronym
- POTATO-2
- Status last verified
- Sep 2026
- First submitted
- 28 Apr 2026
- Last updated
- 28 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 28 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Assessment Of Gut Microbiome Changes During Antibiotic Treatment With Probiotic, Postbiotic Or Placebo: A Randomized, Triple-blind, Placebo-controlled Pilot Study.
- ClinicalTrials.gov ID
- NCT07594860
- Acronym / sponsor ID
- POTATO-2 / CTB2024TN403
- Conditions
- Microbiome
- Keywords
- Antibiotic, Dysbiosis, Microbiome composition, Antibiotic Resistance Genes, Microbiome Recovery, Antibiotic Scarring, Probiotic, Postbiotic
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 126 participants (estimated)
- Lead sponsor
- The Archer-Daniels-Midland CompanyIndustry (pharma, biotech, devices)
- Collaborators
- NEXT CRO
- Study start
- 27 Aug 2026 (actual)
- Primary completion
- 31 May 2027 (estimated)
- Study completion
- 31 May 2027 (estimated)
- First posted
- 19 May 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study assesses the effects of a probiotic or postbiotic on gut microbiome during antibiotic treatment.
Detailed description
The current study aims to assess the changes in microbiome composition in healthy adults receiving antibiotic treatment, and concomitantly a probiotic or postbiotic. The trial will be run in Greece, and will recruit healthy adults from the general population.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Probiotic | Experimental | Dietary Supplement: ProbioticParticipants in this arm will receive a daily dose of a daily dose of of a probiotic (live bacterium), in a form of 2 capsules once daily, for 28 days. |
| Postbiotic | Experimental | Dietary Supplement: PostbioticParticipants in this arm will receive a daily dose of a postbiotic (heat-inactivated bacterium), in a form of 2 capsules once daily, for 28 days. |
| Placebo | Placebo comparator | Dietary Supplement: PlaceboParticipants in this arm will receive an equivalent placebo for the duration of the study (28 days). |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (7 listed)
- Males and females aged ≥18 to ≤ 65 years; if female, either not of childbearing potential or using a medically approved method of birth control and willing to take a pregnancy test at screening.
- Body mass index (BMI) 18.5-29.9 kg/m².
- Healthy as determined by medical history and physical examination.
- Agreed not to change current dietary habits during the course of the study.
- Able to attend study visits, comply with study requirements (consumption of study medications, especially biological sample collection procedures, and study visit schedule) and provide reliable and complete data regarding AEs/SAEs and PROs.
Key exclusion criteria (16 listed)
- Women who are pregnant, breastfeeding, or planning to become pregnant during the course of the study.
- People on vegetarian or vegan diet; People on special diet (e.g. Ducan, Keto, etc.)
- BMI ≥ 30 kg/m² or <18.5 kg/m².
- History of intake of antibiotics, other probiotics, postbiotics, prebiotics, synbiotics, proton pump inhibitors, acid sequestrants (cholestyramine, Bile colestipol), within six months prior to the screening day.
- Participation in other clinical trials in the last 90 days prior to screening.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| ProbioticParticipants in this arm will receive a daily dose of of a probiotic (live bacterium), in a form of 2 capsules once daily, for 28 days. | Dietary supplement | Probiotic |
| PostbioticParticipants in this arm will receive a daily dose of a postbiotic (heat-inactivated bacterium), in a form of 2 capsules once daily, for 28 days. | Dietary supplement | Postbiotic |
| PlaceboParticipants in this arm will receive an equivalent placebo for the duration of the study (28 days). | Dietary supplement | Placebo |
Primary outcome
Changes in gut microbiome composition between baseline and day 14 as compared to placebo.
Time frame: Day 0 and Day 14
To assess the effects of a probiotic or postbiotic in gut microbiome composition of healthy adults receiving antibiotic therapy, as measured by changes in alpha and beta diversity of the gut microbiome as compared to placebo.
7 secondary outcomes
Changes in gut microbiome composition throughout the study as compared to placebo and baseline.
Time frame: Day 0, Day 3, Day 7, Day 28, and Day 56
Changes in abundance of beneficial versus opportunistic/ pathogenic bacterial species throughout the study as compared to baseline and to placebo
Time frame: Day 0, Day 3, Day 7, Day 14, Day 28, and Day 56
Changes in the abundances of microbial genes contained in specific functional modules through the study as compared to baseline and placebo.
Time frame: Day 0, Day 7, Day 14, Day 28, and Day 56
Study the associations of specific microbe abundances with the development of gastrointestinal (GI) symptoms
Time frame: Day 0, Day 3, Day 7, and Day 14
.Changes in the abundances of microbial virulence factors and antibiotic resistant genes through the study as compared to baseline and placebo.
Time frame: Day 0, Day 7, Day 14, Day 28, and Day 56
Safety profile throughout the study as compared to placebo.
Time frame: 56 days
Tolerability of a probiotic or postbiotic as measured by a validated questionnaire and compared to placebo.
Time frame: Day 0, Day 7, Day 14, Day 28, and Day 56
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 28 Oct 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Probiotic and Postbiotic in people with Microbiome, run by The Archer-Daniels-Midland Company at 1 site in Greece.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 7 inclusion and 16 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 28 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Greece. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact ADM Medical Team (+441460243230, medical@protexin.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Changes in gut microbiome composition between baseline and day 14 as compared to placebo. (time frame: Day 0 and Day 14). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 28 Oct 2026.