Microbiota-Oriented Management in Chronic Critical Illness

Chronic critical illness is increasingly recognized as a state in which disruption of the intestinal microbiome may fuel ongoing inflammation and infection. This prospective single‑centre pilot study explored whether a structured microbiome‑oriented management strategy, guided by an integrated microbiota dysfunction score, is feasible, safe, and potentially beneficial in these patients.

Adult ICU patients meeting criteria for chronic critical illness were evaluated using a 0–12‑point Microbiota Dysfunction Degree that combined prior antibiotic exposure, systemic inflammation markers, organ failure assessment, and quantitative microbiological data from the gut. Patients were assigned to mild, moderate, or severe dysfunction categories, which determined a tiered intervention: metabiotic support alone, addition of selective enteral antimicrobials, or a combined gut‑directed and systemic antimicrobial approach designed to limit further damage to commensal anaerobes.

Forty‑three patients were enrolled, with approximately half classified as having mild microbiota dysfunction and the remainder split between moderate and severe categories. Over 14 days of follow‑up, de‑escalation of antimicrobial pressure in those with mild–moderate dysfunction did not lead to clinical deterioration, while improvements were documented in consciousness level, inflammatory indices, and several routine laboratory parameters. Opportunistic Gram‑negative pathogens were common at baseline, but the proportion of samples exceeding reference thresholds for key species, including Klebsiella pneumoniae and Clostridium spp., declined during observation. Across 28 days, the rate of pneumonia was lower than expected for this high‑risk population.

These findings indicate that a graded microbiome‑oriented strategy, anchored in a composite microbiota dysfunction score, can be implemented safely in chronically critically ill patients and may contribute to better infection control and clinical stabilization.