Gut Microbiome in Patients With Post-infectious Irritable Bowel Syndrome (MicroRestore)

April 8, 2026 updated by: IANIRO GIANLUCA, Fondazione Policlinico Universitario Agostino Gemelli IRCCS

Informed Ecological Rewiring of Gut Microbiome for Dysbiosis-associated Disorders

Observational, multicenter, prospective study aimed at characterizing the gut microbiome in patients with post-infectious irritable bowel syndrome (PI-IBS) using whole genome sequencing (WGS). The study will compare microbiome composition and function between PI-IBS patients and two control groups (post-infectious subjects without irritable bowel syndrome -IBS- and healthy controls), with the goal of identifying reproducible microbial signatures and target taxa associated with disease and symptom severity.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Detailed Description

The human gut microbiome plays a key role in host physiology, including immune regulation, metabolism, and protection against pathogens. Alterations in microbiome composition (dysbiosis) have been associated with multiple diseases, including post-infectious irritable bowel syndrome (PI-IBS), a condition that develops after acute gastroenteritis and represents a well-defined model of microbiome disruption.

MicroRestore-1 is a national, multicenter, prospective observational study designed to characterize the gut microbiome of patients with PI-IBS and identify microbial signatures associated with the disease. The study represents Aim 1 of a broader research program investigating precision microbiome modulation strategies.

A total of 315 participants will be enrolled, including 105 PI-IBS patients, 105 post-infectious subjects without IBS, and 105 healthy controls. PI-IBS will be diagnosed according to Rome IV criteria. Eligible participants will undergo baseline clinical assessment, including symptom evaluation using the IBS Severity Scoring System (IBS-SSS), medical history, dietary habits, and lifestyle factors.

Stool samples will be collected at baseline and, for PI-IBS patients, at monthly follow-up visits for three months. Control subjects will provide a single sample at enrollment. All samples will be processed and stored under standardized conditions and analyzed centrally.

Microbiome analysis will be performed using whole genome shotgun sequencing, enabling high-resolution taxonomic and functional profiling. Bioinformatic and statistical analyses, including machine learning approaches, will be used to identify microbial signatures discriminating PI-IBS patients from controls and to explore associations between microbiome features and disease activity.

The primary objective is to identify reproducible microbial signatures and target taxa associated with PI-IBS. Secondary objectives include comparing microbiome composition and function across study groups and evaluating correlations between microbiome features and symptom severity.

This study is expected to provide foundational data for the development of precision microbiome-based therapeutic strategies in PI-IBS.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
315

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • Italy
      • Rome, Italy, 00168
        • Recruiting
        • Digestive Disease Center, Fondazione Policlinico Univesitario A. Gemelli IRCCS
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

Participants will include adults with post-infectious irritable bowel syndrome (PI-IBS) (n= 105) and two control groups: individuals with a history of acute gastroenteritis without persistent gastrointestinal symptoms (n = 105) , and healthy subjects (n = 105) . All participants will be recruited from clinical centers and donor programs and will undergo clinical assessment and stool sample collection for microbiome analysis.

Description

PI-IBS patients (n = 105)

  • Inclusion criteria

    • Age ≥ 18 years old
    • PI-IBS diagnosed according to Rome IV criteria (33).
    • Diagnosis no earlier than 3 months before enrollment.
    • Written informed consent and compliance with study procedures.

  • Exclusion criteria

    • Chronic organic gastrointestinal (GI) disorders (e.g. Inflammatory Bowel Disease -IBD), metabolic syndrome, obesity, diabetes, GI cancers, systemic autoimmune disorders.
    • History of major abdominal surgery.

Control cohort #1 - Post-infectious non-IBS (n = 105)

  • Inclusion criteria

    • Age ≥ 18 years old
    • History of acute infectious gastroenteritis >6 months before enrollment.
    • Complete recovery without persistent GI symptoms.

  • Exclusion criteria

    • Current or past diagnosis of IBS.
    • Any chronic GI or systemic disorders.

Control cohort #2 - Healthy subjects (n = 105)

  • Inclusion criteria

    • Age ≥ 18 years old
    • Healthy donors from FMT program or blood donor program.
    • No history of GI or systemic disorders.

  • Exclusion criteria

    • Any GI or systemic chronic condition.
    • Recent antibiotics/probiotics (<4 weeks).
    • Chronic medication affecting microbiome composition (e.g. PPI)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Post-infectious-IBS patients
Patients diagnosed with post-infectious irritable bowel syndrome (PI-IBS) according to Rome IV criteria. Participants must be ≥18 years old and diagnosed within 3 months prior to enrollment. Clinical data, including IBS severity scoring system (IBS-SSS), medical history, diet, and lifestyle factors will be collected. Stool samples will be collected at baseline and at monthly follow-up visits for 3 months.
Post-infectious non-IBS controls
Adults ≥18 years old with a history of acute infectious gastroenteritis occurring more than 6 months prior to enrollment, with complete recovery and no persistent gastrointestinal symptoms or diagnosis of IBS. One stool sample and associated clinical and lifestyle data will be collected at enrollment.
Healthy controls
Healthy adult subjects ≥18 years old with no history of gastrointestinal or systemic disorders, recruited from fecal microbiota transplantation (FMT) or blood donor programs. Participants must not have taken antibiotics or probiotics within 4 weeks prior to enrollment. One stool sample and associated demographic and lifestyle data will be collected at enrollment.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Identification of microbial signatures discriminating PI-IBS from controls
Time Frame: Baseline up to 30 months (end of study)
Identification of reproducible gut microbiome signatures, including taxonomic and functional profiles, that discriminate patients with post-infectious irritable bowel syndrome (PI-IBS) from control groups using whole genome shotgun sequencing and machine learning approaches.
Baseline up to 30 months (end of study)

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Association between microbiome features and disease severity
Time Frame: Baseline up to 30 months (end of study)
Evaluation of associations between gut microbiome composition and function and disease activity, as measured by the IBS Severity Scoring System (IBS-SSS).
Baseline up to 30 months (end of study)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Fondazione Policlinico Universitario Agostino Gemelli IRCCS

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Gianluca Ianiro, Fondazione Policlinico Universitario A. gemelli, IRCCS

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
April 8, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
October 1, 2028

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 1, 2028

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
April 1, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 1, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
April 8, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
April 13, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 8, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
April 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 26967

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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