Precision Modulation of Gut Microbiome Enteropathogen Colonization in Critical Illness

Inclusion Criteria: * Adult (\>18 years old) admitted to FMC ICU within 48h of admission * Mechanically ventilated via endotracheal tube * Expected duration of mechanical ventilation \>72 hours from time of screening (as determined by attending ICU physician) Exclusion Criteria: * Goals of care designation that limits the use of life-sustaining interventions * Life expectancy \<72 hours (in the opinion of the attending ICU physician) * Unable to receive enteral administration of medications * Presence of ileus, discontinuous GI tract (including ileostomy), total or partial colectomy, bariatric surgery, inflammatory bowel disease, active graft-versus-host disease, cirrhosis with Child-Pugh Class C, or short bowel syndrome * Acute immunosuppression including recent (within 30 days) cytotoxic chemotherapy; chronic systemic steroids (≥20 mg prednisone equivalent/day for \>3 weeks); uncontrolled HIV infection (with CD4 count \<400/μl); neutropenia (absolute neutrophil count \<500/μL) * Pregnancy or breastfeeding * Concurrently taking pre-, pro-, synbiotic, or live biotherapeutic product, or other fermented food product and unwilling to discontinue these for the duration of the study * Concurrently enrolled in another clinical trial of pre-, pro-, synbiotic, or live biotherapeutic product, antimicrobial, or immune modulator therapy * History of lactose allergy (lactose intolerance not exclusionary) * Unsuitable for inclusion in study in the opinion of the attending physician or investigator