Gut Microbiome in Patients With Post-infectious Irritable Bowel Syndrome

NCT07517029 | Recruiting

• 1 other identifier: 26967
• Study Type: observational
• Target: 315
• Locations: 1 country
• Sites: 1

Brief Summary

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.

Conditions

Post Infection Syndrome; IBS - Irritable Bowel Syndrome

Outcome Measures

Primary Outcomes (1)

• Identification of microbial signatures discriminating PI-IBS from controls

  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 Outcomes (1)

• Association between microbiome features and disease severity

  Baseline up to 30 months (end of study)

Study Arms (3)

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.

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)
• 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.

You may qualify if:

• 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.

You may not qualify if:

• 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)
• Age ≥ 18 years old
• History of acute infectious gastroenteritis \>6 months before enrollment.
• Complete recovery without persistent GI symptoms.
• Current or past diagnosis of IBS.
• Any chronic GI or systemic disorders.
• Control cohort #2 - Healthy subjects (n = 105)
• Age ≥ 18 years old
• Healthy donors from FMT program or blood donor program.
• No history of GI or systemic disorders.
• Any GI or systemic chronic condition.
• Recent antibiotics/probiotics (\<4 weeks).
• Chronic medication affecting microbiome composition (e.g. PPI)

Sponsors & Collaborators

• Fondazione Policlinico Universitario Agostino Gemelli IRCCS: lead

Study Sites (1)

Digestive Disease Center, Fondazione Policlinico Univesitario A. Gemelli IRCCS

Rome, 00168, Italy

RECRUITING

Biospecimen

Retention: SAMPLES WITH DNA

Stool samples will be collected from all participants. In PI-IBS patients, samples will be collected at baseline and at monthly follow-up visits for 3 months. Control subjects will provide one stool sample at enrollment. Samples will be collected using a preservation buffer, and stored at -80°C with de-identified IDs. DNA will be extracted for whole genome shotgun sequencing to perform taxonomic and functional microbiome profiling.

MeSH Terms

Conditions

Irritable Bowel Syndrome; Post-Infectious Disorders

Condition Hierarchy (Ancestors)

Colonic Diseases, Functional; Colonic Diseases; Intestinal Diseases; Gastrointestinal Diseases; Digestive System Diseases; Chronic Disease; Disease Attributes; Pathologic Processes; Pathological Conditions, Signs and Symptoms

Study Officials

• Gianluca Ianiro

  Fondazione Policlinico Universitario A. Gemelli, IRCCS

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Gianluca Ianiro

CONTACT

+390630155701; gianluca.ianiro@policlinicogemelli.it

Study Design

• Study Type: observational
• Observational Model: CASE CONTROL
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator, MD, PhD

Study Record Dates

• First Submitted: April 1, 2026
• First Posted: April 8, 2026
• Study Start: April 8, 2026
• Primary Completion (Estimated): October 1, 2028
• Study Completion (Estimated): December 1, 2028
• Last Updated: April 13, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will not share

Locations

IT (1)