Antibiotics, Gastric Bypass, and the Microbiome
Condition: Obesity, Morbid; Hypertension; Bariatric Surgery Candidate
MeSH terms: Obesity, Morbid
Study type: Interventional
Phase: Phase 1

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.
    

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.
    

Intervention name(s): Antibiotic
Intervention type(s): Drug
Intervention description(s): Peri-operative, intravenous antibiotic for surgical site infection
Intervention MeSH terms: Anti-Bacterial Agents
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: gut microbiome