The goal of this observational study is to learn about the long-term effects of fecal microbiota transplantation (FMT) compared with antibiotic-only treatment in adults who were treated for Clostridioides difficile infection (CDI) at Umeå University Hospital between 2016 and 2024. The main questions it aims to answer are: * Do patients treated with FMT maintain higher gut bacterial diversity up to 10 years after CDI compared with patients treated with antibiotics only? * Do donor gut bacteria introduced by FMT persist long-term in the recipient's gut? * Are there differences in gut metabolism, gut barrier function, and systemic inflammation between FMT-treated and antibiotic-only treated patients at long-term follow-up? * What are the long-term safety outcomes - including new diseases, hospitalizations, and mortality - in FMT-treated versus antibiotic-only treated patients? Researchers will compare patients who received FMT to patients who received antibiotics only to see if FMT leads to lasting differences in gut microbiota, metabolism, immune markers, and clinical outcomes. Participants will: * Attend a single study visit at Umeå University Hospital * Provide samples of blood, stool, urine, and a nasal swab * Complete two quality-of-life questionnaires Clinical data will be collected from medical records for all participants.
Study design and setting This is a single-center, long-term observational cohort study conducted at the Department of Infectious Diseases, Umeå University Hospital, Sweden. The study enrolls adult patients treated for CDI between February 1, 2016 and December 31, 2024, providing up to 10 years of follow-up from the index CDI episode. Participants are stratified into two groups: FMT-treated and antibiotic-only treated. CDI case definition Compatible clinical presentation (≥3 loose stools in 24 hours) plus a positive nucleic acid amplification test (LAMP) for C. difficile, consistent with ESCMID diagnostic criteria. Recruitment Potentially eligible living subjects are identified from departmental diagnosis records and contacted by mail with written study information and an opt-out form. Those who do not return the opt-out form are contacted by telephone and invited to a single study visit for informed consent and enrollment. Deceased individuals are included in safety analyses only, without contact with next of kin. Biological sampling Blood: EDTA plasma, serum, PBMC isolation Fecal sample Urine sample Nasopharyngeal swab Archived donor fecal samples and pre- and post-FMT patient samples from the Umeå FMT biobank will be retrieved for longitudinal comparisons. Observational measures Gut and nasopharyngeal microbiota will be characterized by shotgun metagenomics (strain-level resolution) and 16S rRNA sequencing. Resistome profiling and detection of multidrug-resistant organisms by culture will be performed on fecal samples. Global and targeted metabolomics (short-chain fatty acids, bile acids, redox metabolites) will be performed on feces, urine, and blood. Gut barrier markers in blood will include LPS, LPS-binding protein (LBP), and EndoCAb. Systemic immune profiling will include cytokine panels, soluble immune mediators, antibodies, and transcriptomic profiling of peripheral blood mononuclear cells. The host genome will not be sequenced. Clinical observational measures will include additional CDI after index CDI. Pharmacological treatments and comorbidity at index CDI and follow-up, as well as any antibiotic exposure during follow-up will be collected from the medical records.
Study Type
OBSERVATIONAL
Enrollment
250
Umeå University Hospital
Umeå, Sweden
Intestinal microbiota diversity
Intestinal microbiota diversity assessed by metagenomic sequencing of stool samples.
Time frame: At follow-up visit 1-10 years after baseline CDI
Donor gut microbiota long-term engraftment
Assessment of donor gut microbiota engraftment in participants stool samples 1-10 years post FMT, performed by metagenomic sequencing.
Time frame: At follow-up visit 1-10 years after baseline CDI
Stool short-chain fatty acid concentrations
Stool short-chain fatty acid concentrations assessed using metabolomic methods.
Time frame: At follow-up visit 1-10 years after baseline CDI
Circulating markers of intestinal barrier function
Circulating biomarkers related to intestinal barrier function measured in peripheral blood.
Time frame: At follow-up visit 1-10 years after baseline CDI
Health-related quality of life
Patient-reported health-related quality of life assessed using the EuroQol 5-Dimension 5-Level questionnaire (EQ-5D-5L). The descriptive system comprises five dimensions (mobility, self-care, usual activities, pain/discomfort, and anxiety/depression), each with five levels (no problems to extreme problems), producing a 5-digit health state profile. Higher index values indicate better health-related quality of life.
Time frame: At follow-up visit 1-10 years after baseline CDI
Number of participants with new Clostridioides difficile infection episodes after subsequent antibiotic exposure
Occurrence of new Clostridioides difficile infection episodes following exposure to non-CDI antibiotic treatment during follow-up.
Time frame: Within 1-10 years after baseline CDI
Incidence of new comorbidities after FMT versus antibiotic-only treatment
Incidence of new diagnoses (autoimmune, autoinflammatory, neoplastic, and metabolic conditions) in FMT-treated participants compared with antibiotic-only treated participants, ascertained from medical records using ICD-10 diagnostic codes.
Time frame: From baseline CDI to 1-10 year follow-up or prior death
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