Analysis of the Composition of the Intestinal Microbiota in Patients Post-intestinal Anastomosis (MIDESIN)

Analysis of the Composition of the Intestinal Microbiota and Its Evolution in Patients Post-intestinal Anastomosis

Recent research suggests a significant link between gut microbiota and anastomotic leakage (AL) in colorectal surgery. Patients who develop AL have a higher abundance of bacteria from the Lachnospiraceae family and lower microbial diversity.

Considering the bibliographic data, our main interest is to analyze the microbial population of patients in our social environment and then look for differences in the microbiome between those who have suffered an anastomotic dehiscence (around 8-9% according to the results of our hospital's Surgery Department) and those who have not.

Study Overview

• Status: Recruiting
• Conditions: Abdominal Surgery
• Intervention / Treatment: Other: Not applicable- observational study

Detailed Description

The study is designed as a prospective, descriptive, non-interventional research project in which some variables will be analyzed transversally. Patients will be selected by the clinical members of the research team from within the population in our setting who will undergo abdominal surgery involving colorectal intestinal anastomosis. Once accepted, stool samples will be requested prior to surgical preparation, during surgery, and afterwards to determine their microbiome; in this way, we will attempt to correlate the evolution of their anastomosis with their intestinal bacterial population.

• Study Type: Observational
• Enrollment (Estimated): 30

Contacts and Locations

• Study Contact: Name: Héctor Guadalajara-Labajo, MD, PhD; Phone Number: 4331 + 34 550 4800; Email: h.guadalajara@quironsalud.es

Study Locations

• Spain
  • Madrid, Spain, 28040
    • Recruiting
    • University Hospital Fundación Jiménez Díaz
    • Contact: Héctor Guadalajara-Labajo, MD, PhD; Phone Number: 4331 +34 915504800; Email: h.guadalajara@quironsalud.es
    • Contact: Mariano García-Arranz, PhD; Phone Number: 3398 +34 91 5504800; Email: mariano.garcia@iis-fjd.es

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Patients will be selected by the clinical members of the research team from within the population in our setting who will undergo abdominal surgery involving colorectal intestinal anastomosis. To identify patients, the Surgery Department will analyze those who meet the inclusion and exclusion criteria designed for this project during the daily morning clinical session, and patients will then be offered the opportunity to accept/decline participation.

Description

Inclusion Criteria:

• Patients who have undergone colorectal intestinal anastomosis.
• Signing of the informed consent form.
• Age ≥18 years with good functional status.
• Availability for postoperative follow-up.

Exclusion Criteria:

• Emergency surgery.
• Intra-abdominal sepsis or previous dehiscence.
• Severe immunosuppression.
• Use of antibiotics in the 3 months prior to preoperative preparation.
• Pregnancy or breastfeeding.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Patients undergoing abdominal surgery with intestinal anastomosis; Older than 18 years of age	Other: Not applicable- observational study; Fecal sample collection

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Understand the patient's microbiome	To understand the microbiome of patients undergoing colorectal surgery and the effect of current surgical preparation on the microbiota in our local population.	From enrollment to a month post surgery

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Predictive indicators of colorectal anastomosis postsurgery	Predictive indicators of postoperative outcomes in patients undergoing colorectal anastomosis surgery through metagenomic characterization of the gut microbiota.	From surgery to a month

Collaborators and Investigators

• Sponsor: Instituto de Investigación Sanitaria de la Fundación Jiménez Díaz
• Investigators: Principal Investigator: Mariano García-Arranz, PhD, Health Research Institute Fundación Jiménez Díaz

Publications and helpful links

General Publications

• Jørgensen AB, Almer L, Brandstrup B, Friis-Hansen L. Fecal microbiomes from screening sampling tubes are stable despite varying sampling and storage conditions. Sci Rep. 2025 Jul 24;15(1):26951. doi: 10.1038/s41598-025-12506-5.
• Hajjar R, Richard C, Santos MM. The gut barrier as a gatekeeper in colorectal cancer treatment. Oncotarget. 2024 Aug 14;15:562-572. doi: 10.18632/oncotarget.28634.
• Lianos GD, Frountzas M, Kyrochristou ID, Sakarellos P, Tatsis V, Kyrochristou GD, Bali CD, Gazouli M, Mitsis M, Schizas D. What Is the Role of the Gut Microbiota in Anastomotic Leakage After Colorectal Resection? A Scoping Review of Clinical and Experimental Studies. J Clin Med. 2024 Nov 5;13(22):6634. doi: 10.3390/jcm13226634.
• Hoedt EC, Carroll GM, Stephensen BD, Morrison M, Vishnoi V, Cuskelly A, Draganic BD, McManus B, Clarke L, Shah KH, Smith SR, Talley NJ, Keely S, Pockney P. Preoperative Antibiotics and Mechanical Bowel Preparation Impact the Colonic Mucosa-Associated Microbiota but Not Anastomotic Leak Rate After Colorectal Resection. Dis Colon Rectum. 2025 Jul 1;68(7):875-886. doi: 10.1097/DCR.0000000000003775
• Xiong Z, Liu J, Chen L, Yang Y, Zhao S. Precision leak detection in the golden window: emerging biomarker strategies for anastomotic integrity monitoring after low anterior resection. Int J Surg. 2025 Oct 1;111(10):7125-7134. doi: 10.1097/JS9.0000000000002891
• Ma K, Gu T, Wu Z, Li Z. Mechanisms of anastomotic leakage in colorectal cancer surgery: unraveling the roles of inflammation, immunity, and microbiota - a narrative review. Int J Surg. 2025 Aug 7. doi: 10.1097/JS9.0000000000003151
• Barat B, Shogan BD. The Microbiome's Role in Driving Anastomotic Leak and Cancer Recurrence Following Colorectal Surgery. Surg Clin North Am. 2025 Oct;105(5):953-964. doi: 10.1016/j.suc.2025.06.003.
• van Praagh JB, de Goffau MC, Bakker IS, Harmsen HJ, Olinga P, Havenga K. Intestinal microbiota and anastomotic leakage of stapled colorectal anastomoses: a pilot study. Surg Endosc. 2016 Jun;30(6):2259-65. doi: 10.1007/s00464-015-4508-z. Epub 2015 Sep 18. PMID: 26385781
• Yan J, Wang Q, Li Q, Lu J, Tong Q. Differences in gut microbiota among patients with anastomotic leak following colorectal cancer surgery. Front Microbiol. 2025 Oct 6;16:1578990. doi: 10.3389/fmicb.2025.1578990. PMID: 41122462;

Study record dates

Study Major Dates

• Study Start (Actual): February 14, 2026
• Primary Completion (Actual): February 14, 2026
• Study Completion (Estimated): December 14, 2026

Study Registration Dates

• First Submitted: December 4, 2025
• First Submitted That Met QC Criteria: February 13, 2026
• First Posted (Actual): February 18, 2026

Study Record Updates

• Last Update Posted (Actual): February 18, 2026
• Last Update Submitted That Met QC Criteria: February 13, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: Microbiome; intestinal anastomosis; dehiscence
• Other Study ID Numbers: PIC165-25_FJD (Other Identifier: Clinical Research Ethics Committee)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Publication of results in open access. Presentation at national surgery conferences.
• IPD Sharing Time Frame: Between 6-12 months
• IPD Sharing Access Criteria: Open access
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No