The goal of this clinical trial is to learn if daily oral supplementation with pasteurized Akkermansia muciniphila (PAM), an EFSA-approved food supplement, can support recovery in adults who have recently been treated in the ICU for sepsis.

The main questions it aims to answer are:

• Is PAM safe to take for 56 days after ICU discharge?
• Does PAM increase the abundance of beneficial butyrate-producing bacteria in the gut?

Researchers will compare PAM to a placebo (a capsule that looks the same but has no active ingredient) to see if PAM improves gut microbiota and immune recovery.

Participants will:

• Take PAM or placebo capsules once daily for 56 days
• Provide stool and blood samples at baseline, day 28, and day 56
• Receive a follow-up phone call about their health 1 year after starting the study

Inclusion Criteria:

• Age ≥18 years
• Treated in the ICU for at least 2 days and discharged to a regular clinical ward
• Diagnosed with sepsis during ICU admission
• Received selective digestive decontamination (SDD) or cephalosporin
• Capable of giving written informed consent

Exclusion Criteria:

• Recent major gastrointestinal surgery
• Diagnosed with ulcerative colitis or Crohn's disease
• Presence of a hematological malignancy and/or current use of immunomodulatory therapy (e.g., CAR-T cell therapy or immune checkpoint inhibitors) Use of systemic immunomodulatory drugs or corticosteroids (defined as ≥10 mg prednisone equivalent daily at ICU discharge), at the time of inclusion.
• History of solid organ or stem cell transplantation
• Pregnancy or lactation
• Donation of blood or plasma within 30 days prior to inclusion or planned donation during the intervention period
• Any other condition that, in the opinion of the investigator, could pose a risk to the subject or interfere with study result

This is a double-blind, placebo-controlled trial. Participants, care providers, investigators, and outcomes assessors are masked to intervention assignment.