Enteral Nutrition and Colonization Resistance Through Microbiota Modulation in Critically Ill Patients (MICRON)

July 20, 2026 updated by: Andra-Elena Goicea, Iuliu Hatieganu University of Medicine and Pharmacy

Enteral Nutrition to Enhance Colonization Resistance Through Gut Microbiota Modulation in Critically Ill Patients: A Randomized Controlled Pilot Trial

The goal of this clinical trial is to learn whether enteral nutrition enriched with fiber can influence gut microbiota and improve resistance to colonization with multidrug-resistant bacteria in critically ill patients. The study will also evaluate the safety and clinical outcomes associated with fiber-enriched enteral nutrition.

The main questions it aims to answer are:

  • Does fiber-enriched enteral nutrition reduce the acquisition of colonization with multidrug-resistant bacteria during intensive care unit (ICU) hospitalization?
  • Does fiber-enriched enteral nutrition modify the composition and diversity of the intestinal microbiota?
  • Are there differences in clinical outcomes, including adverse events, between patients receiving fiber-enriched and non-fiber enteral nutrition?

Researchers will compare patients receiving fiber-enriched enteral nutrition with patients receiving standard enteral nutrition without added fiber to determine whether fiber supplementation influences gut microbiota and colonization resistance.

Participants will:

  • Receive enteral nutrition through a feeding tube according to their clinical needs.
  • Receive either a fiber-enriched enteral nutrition formula or a standard enteral nutrition formula.
  • Have stool samples collected during ICU hospitalization for analysis of intestinal microbiota and detection of multidrug-resistant bacteria.
  • Be monitored for clinical outcomes, infections, antibiotic exposure, and adverse events during their ICU stay and follow-up period.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Critically ill patients frequently experience alterations of the intestinal microbiota due to factors such as severe illness, antibiotic exposure, and the ICU environment. These changes may contribute to loss of colonization resistance and increased susceptibility to acquisition of multidrug-resistant bacteria, which are associated with increased morbidity and mortality in critically ill populations.

Enteral nutrition is commonly used in ICU patients who are unable to meet their nutritional requirements orally. Beyond its role in providing calories and nutrients, enteral nutrition may influence intestinal barrier function and microbiota composition. Fiber-containing enteral formulas include nondigestible carbohydrates that may act as substrates for microbial fermentation and may promote the growth of beneficial bacterial populations and the production of short-chain fatty acids.

Previous studies have suggested that fiber supplementation during enteral nutrition may influence gut microbiota composition and clinical outcomes; however, results remain inconsistent, particularly in critically ill patients receiving broad-spectrum antibiotics. The potential effect of fiber-enriched enteral nutrition on acquisition of multidrug-resistant bacterial colonization has not been adequately investigated.

This clinical trial aims to evaluate whether modulation of the intestinal microbiota through fiber-enriched enteral nutrition may influence colonization resistance in critically ill patients. The study will provide preliminary data regarding microbiota changes associated with enteral nutrition strategies and their potential relationship with multidrug-resistant bacterial colonization. These findings may support the design of future larger clinical trials evaluating nutritional interventions as a strategy to preserve microbiome function and reduce ICU-associated complications.

Study Type

Interventional

Enrollment (Estimated)

60

Phase

  • Not Applicable

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 Locations

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

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Patients with medical (non-surgical) conditions admitted to the ICU.
  • ICU admission within the previous 48 hours at the study site.
  • Initiation of enteral nutrition within the first 48 hours after ICU admission.
  • Written informed consent obtained for participation in the study.

Exclusion Criteria:

  • Surgical ICU patients.
  • Patients in whom enteral nutrition was not initiated within the first 48 hours after - ICU admission.
  • Patients with galactosemia.
  • Patients with major contraindications to enteral nutrition, including: intestinal obstruction, intestinal ischemia, intestinal perforation, severe hemodynamic instability, patients who refuse participation in the study.

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

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Fiber-Enriched Enteral Nutrition
Participants will receive an enteral nutrition formula containing dietary fiber according to the study protocol.
Dietary supplement: Fibre-Enriched Enteral Nutrition
Participants will receive enteral nutrition administered through an enteral feeding tube according to their clinical nutritional requirements. The intervention consists of an enteral nutrition formula enriched with dietary fiber, including fermentable fibers with potential prebiotic effects, intended to modulate intestinal microbiota composition and function. It will be administered according to the study protocol and clinical care requirements of critically ill patients. The intervention will be initiated during intensive care unit hospitalization and continued according to patient tolerance and clinical indications. The type and amount of enteral nutrition administered will be documented throughout the study period.
Other Names:
  • enteral feeding
  • tube feeding
Active Comparator: Standard Enteral Nutrition Without Fiber
Participants will receive an enteral nutrition formula without added dietary fiber according to the study protocol.
Dietary supplement: Standard Enteral Nutrition
Participants will receive enteral nutrition administered through an enteral feeding tube according to their clinical nutritional requirements. The comparator intervention consists of a standard enteral nutrition formula without added fiber. It will be administered according to the study protocol and clinical care requirements of critically ill patients. The type and amount of enteral nutrition administered will be documented throughout the study period.
Other Names:
  • enteral feeding
  • tube feeding

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Proportion of Participants With New Multidrug-Resistant Bacterial Colonization Between Days 5 and 7
Time Frame: ICU days 5-7 after admission
Proportion of participants who acquire new colonization with multidrug-resistant bacteria (MDRB) during ICU hospitalization, assessed between study days 5 and 7. New colonization will be defined as detection of MDRB not present at baseline (day 0) based on microbiological surveillance samples.
ICU days 5-7 after admission

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Gut Microbiota Diversity and Composition
Time Frame: From ICU admission (Day 1) to ICU days 5-7
Changes in intestinal microbiota diversity and composition between baseline and follow-up samples, assessed by microbiome analysis of stool samples.
From ICU admission (Day 1) to ICU days 5-7
Proportion of Participants With MDRO Colonization at Day 14 and 28
Time Frame: Day 14 and 28 after ICU admission
Proportion of participants with MDRB colonization detected on surveillance microbiological samples among participants who continue receiving enteral nutrition.
Day 14 and 28 after ICU admission
Incidence of Nosocomial Infections
Time Frame: From ICU admission (Day 1) to hospital discharge or Day 28, whichever occurs first
Incidence and type of nosocomial infections occurring during ICU hospitalization.
From ICU admission (Day 1) to hospital discharge or Day 28, whichever occurs first
Duration of Mechanical Ventilation and Ventilator-Free Days
Time Frame: Day 28 after ICU admission
Duration of invasive mechanical ventilation and number of ventilator-free days during the first 28 days after ICU admission.
Day 28 after ICU admission
Duration of ICU and Hospital Stay
Time Frame: ICU stay: From ICU admission through ICU discharge, an average of 28 days; Hospital stay: From hospital admission through hospital discharge, an average of 90 days.
Duration of intensive care unit stay and total hospital length of stay.
ICU stay: From ICU admission through ICU discharge, an average of 28 days; Hospital stay: From hospital admission through hospital discharge, an average of 90 days.
28-Day Mortality and In-Hospital Mortality
Time Frame: 28-Day Mortality: 28 days after ICU admission; In-Hospital Mortality: during the hospital stay, up to hospital discharge, up to 90 days.
All-cause mortality occurring within 28 days after ICU admission and during the index hospital admission.
28-Day Mortality: 28 days after ICU admission; In-Hospital Mortality: during the hospital stay, up to hospital discharge, up to 90 days.
Correlation Between Immunological and Inflammatory Profile Changes and MDRB Colonization or Microbiota Changes
Time Frame: From ICU admission (Day 1) to Day 28 after ICU admission
Correlation between longitudinal changes in inflammatory and immunological markes, and changes in MDRB colonization status and intestinal microbiota composition. Biomarkers will include routine laboratory parameters (e.g., leukocyte differential count, C-reactive protein, fibrinogen, erythrocyte sedimentation rate, ferritin) and immunological markers (e.g., immunoglobulins IgA, IgG, IgM, IgE, complement C3 and C4), and will be reported using their respective standard clinical laboratory units. MDRB colonization will be assessed by microbiological culture and reported for ESBL-producing organisms, CRE, MRSA, VRE. Intestinal microbiota composition will be characterized by next-generation sequencing and reported using taxonomic relative abundance and diversity indices.
From ICU admission (Day 1) to Day 28 after ICU admission

Collaborators and Investigators

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

Sponsor

Iuliu Hatieganu University of Medicine and Pharmacy

Investigators

  • Study Chair: Constantin Bodolea, "Iuliu Hațieganu" University of Medicine and Pharmacy Cluj-Napoca

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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 (Estimated)

October 1, 2026

Primary Completion (Estimated)

October 1, 2027

Study Completion (Estimated)

December 1, 2027

Study Registration Dates

First Submitted

July 14, 2026

First Submitted That Met QC Criteria

July 20, 2026

First Posted (Actual)

July 22, 2026

Study Record Updates

Last Update Posted (Actual)

July 22, 2026

Last Update Submitted That Met QC Criteria

July 20, 2026

Last Verified

July 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • DEP227/25.06.2026

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data will not be shared because the study involves a relatively small number of critically ill patients and includes detailed clinical and microbiological information that may present privacy and confidentiality risks. Data will be handled according to applicable ethical and data protection requirements.

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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