Gut Decolonisation With Neomycin/Metronidazole or Rifaximin Before Colon Surgery

Neomycine/Metronidazole- vs Rifaximin-based Gut Decolonisation Prior to Colon Surgery: a Randomized Multicenter Trial

The goal of this clinical trial is to find out if a gut cleaning using Rifaximin works as well as the usual treatment with Neomycin and Metronidazole to prevent infections after colon surgery. The study includes adult patients who will have colon surgery.

The main question it aims to answer are:

-Does the Rifaximin treatment prevent surgical site infections as well as the Neomycin/Metronidazole treatment?

Other things the study will look at:

• How often infections happen, stratified on how deep they are, the type of surgery the patients got, or if bowel cleaning was done before surgery.
• How many people will die after surgery
• How long people stay in hospital

Participants will:

• Take either Rifaximin or Neomycin/Metronidazole one day before surgery to clean their gut
• Keep a diary until the surgery to record medication intake and any side effects
• Be contacted by phone 30 days after surgery to ask about their condition and any side effects,

Surgical site infections (SSIs) are the most frequent infections in patients undergoing colon surgery, leading to considerable morbidity, mortality and increased healthcare costs. As SSIs are often caused by endogenous gut flora, oral antibiotic gut decolonisation prior to colon surgeries is standard practice. However the optimal antibiotic regimen remains unclear.

This phase IV, multicenter, open-label randomized controlled trial aims to evaluate whether a rifaximin-based protocol is non-inferior to the current standard regimen of neomycin and metronidazole in preventing SSIs.

Rifaximin is a semi-synthetic derivate with poor systemic absorption, allowing for local gut action and a broad antibacterial spectrum covering gram-positiv, - negativ, aerobic aswell as anaerobic bacteria. It is approved in Switzerland for hepatic encephalopathy and has a favorable safety profile with mostly mild gastrointestinal side effects. Neomycin is FDA-approved for preoperative gut decolonisation. Common side effects include nausea, vomiting and diarrhea.

The study will include about 458 patients undergoing planned colon surgery at five swiss hospitals. Patients will be randomized in 1:1 ratio to receive either rifaximin 2x550mg per day or Neomycin 2x500mg plus Metronidazol 2x500mg per day, administeres orally at 10:00 AM and 10:00 PM on the day before surgery. Mechanical bowel preparation, when applied, is scheduled between 4:00 PM and 08:00 PM on the same day. The primary outcome is the incidence of SSI. Secondary outcomes include mortality and length of hospital stay.

Ramdomization is computer-generated. Blinding is limited to the responsible statisticians. Clinicians and patients are aware of the assigned treatment. Safety assessments focus on known side effects as documentes by reculatory agencies.

The study adresses a clinically important gap in evidence for the best antibiotic regimen for preoperative gut decolonisation.

Inclusion Criteria:

• aged ≥ 18 years
• undergoind planned colon surgery
• colon surgery will be included in Swissnoso SSI surveillance
• informed consent

Exclusion Criteria:

• contraindications and/or intolerance to one of the study compounds
• patients with underlying active infection (wound contamination class IV) at the timepoint of incision
• pregnant women
• unable to follow study protocol