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CompletedNCT05367479Updated May 10, 2022

Antibiotics, Gastric Bypass, and the Microbiome

A Phase 1 interventional study of Antibiotic in Obesity, Morbid, Hypertension and Bariatric Surgery Candidate, sponsored by Medical College of Wisconsin. Completed at 1 site in United States. Open to participants aged 18 Years to 70 Years. Per ClinicalTrials.gov, last updated 2022-05-10.

Sponsored by Medical College of Wisconsin · Phase 1, Interventional, and Basic science

From the registry’s dates

  • Primary completion was Jan 2020, 6 years 8 months ago, and no results have been posted to the registry.
  • Registered 3 years 9 months after the study started (first participant enrolled Jul 2018, registered May 2022).
Phase
Phase 1
Study type
Interventional
Enrollment
23
Allocation
Randomized
Ages
18 Years to 70 Years
Sex
All
01

Study summary

This study randomizes patients to two commonly used peri-procedural antibiotics after gastric bypass with the pre and post-operative collection of stool samples, to identify significant differences in relative abundances of gut microbiota phyla, genera and species between the two antibiotic groups used. Gastric bypass may beneficially affect hypertension by altering the post-operative microbiome and specific antibiotics can further enhance the resolution rate by improving microbial diversity and richness.

Read the detailed description

Eligible patients will be reviewed to meet inclusion criteria. Patients will be approached for enrollment at their pre-operative clinic appointment. If patients agree, consent will be signed.

Demographics will be collected on all patients including past medical, surgical and obesity history. Blood pressure will be recorded in the office, hypertensive medication record reviewed, post-operative follow-up and stool samples will be collected at 5 visits (V1-V5): 2 weeks pre-op, day of surgery, 2 weeks post-op, and 3 months post-op. Patients will be randomized at the time of surgery to receive intravenous cefazolin or clindamycin (weight-based dosing) as a pre-operative antibiotic within 60 minutes of incision time. Both antibiotics are routinely used as a single intravenous pre-operative dose for surgical site infection prophylaxis during Roux-en-Y gastric bypass and does not alter the standard of care. In routine care, clindamycin is given when there is a cefazolin allergy. Vancomycin is given if there is an allergy to both. We have a protocol that all bariatric surgeons follow rather than preference. There should be equipoise regarding the risk of a skin, superficial or deep surgical site infection between the two choices.

Hypertension will be considered resolved when the blood pressure is \<140/90 without medication. Data points for collection were chosen to identify both short and long-term changes in the microbiome as well as assess for changes in the microbiome related to dietary modifications required with surgery.

Stool samples will be collected from participants in this study. Stool samples will be collected at the convenience of the participant at time points designated in the study design. The participant will be given a stool sample kit(s) to take home during the time of consent. The stool sample will be received by the research laboratory at a follow-up visit, or returned via FedEx with materials supplied in the stool collection kit. Following receipt in the laboratory, the stool samples will be stored in Dr. Kindel's lab (4th floor CRI) at -80 degrees where they will later undergo bacterial genomic DNA and RNA isolation using standardized techniques and later analysis for 16S and metagenomic sequencing analysis.

02

Conditions studied

  • Obesity, Morbid
  • Hypertension
  • Bariatric Surgery Candidate

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Keywords

  • gut microbiome
03

In context

Obesity, Morbid

922 studies on the registry are indexed under Obesity, Morbid; 172 are open to participants now.

This study's enrollment of 23 is below the median of 60 across 590 interventional studies indexed under Obesity, Morbid.

Browse Obesity, Morbid studies →

Lead sponsor

Medical College of Wisconsin is the lead sponsor of 540 studies on the registry; 120 are open to participants now.

Of its 71 completed or terminated interventional studies of FDA-regulated products, 56 (79%) have results posted.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years to 70 Years
Sexes eligible
All
Accepts healthy volunteers
No

Eligibility criteria

Inclusion Criteria: Patients who are approved for a primary RYGB at MCW's bariatric surgery program as treatment for morbid obesity and obesity-associated co-morbidities. Patients will be eligible who are: 1.) female or male 2.) 18-70 years of age, 3.) hypertensive

Exclusion Criteria: Patients are ineligible if they: 1.) have a diagnosis of cirrhosis, 2.) are taking antibiotics, probiotics, or immune modulating medications for one month prior to or after surgery, 3.) have a history of bowel resections, inflammatory bowel disease and/or celiac disease, 4.) have a life-threatening reaction to penicillin/cephalosporins or clindamycin.

05

Study design

Phase
Phase 1
Primary purpose
Basic science
Allocation
Randomized
Intervention model
Parallel assignment
Masking
None (open label)
Enrollment
23 participants (actual)

Study arms

  • Active comparator
    Cefazolin

    standard of care as a pre-operative antibiotic given with 60 minutes of incision before gastric bypass surgery. given intravenous as a single dose, weight based.

    Drug: Antibiotic

  • Active comparator
    Clindamycin

    also standard of care alternative as a pre-operative antibiotic given with 60 minutes of incision before gastric bypass surgery. given intravenous as a single dose, weight based.

    Drug: Antibiotic

Interventions

  • DrugAntibiotic

    Peri-operative, intravenous antibiotic for surgical site infection

06

What researchers measure

Primary outcomes

  1. operational taxonomic units

    a distinct bacterial community

    Time frame: 3 months postoperatively

07

Study locations

1 site
  • Froedtert Hospital
    Milwaukee, Wisconsin 53226, United States
08

References and documents

Individual participant data

Plan to share: No

No publications or documents are linked to this record.

09

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on May 10, 2022, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT05367479
Lead sponsor
Medical College of Wisconsin
Responsible party
Tammy Kindel, MD, PhD (Associate Professor, Medical College of Wisconsin) — Principal investigator
First posted
May 10, 2022
Start date
Jul 18, 2018
Primary completion
Jan 9, 2020
Completion
Jan 9, 2020
Last update
May 10, 2022

Oversight

Data monitoring committee
No
FDA-regulated drug
Yes
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

Not currently enrolling

This study is completed, as verified in May 2022. You cannot join it, but the record below documents what was studied.

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