Gut Colonization With Vancomycin-Resistant Enterococcus Shapes the Gut Microbiome in the Intensive Care Unit.

Summary

In 90 ICU patients with sepsis on broad-spectrum antibiotics, VRE colonization peaked by ICU day 14, coinciding with marked Enterococcus dominance and reduced alpha diversity, with partial reversion by day 30. These longitudinal dynamics pinpoint windows for targeted decolonization or microbiome-preserving interventions.

Key Findings

• VRE positivity increased from 20% at ICU admission to 33% by ICU day 14, then slightly declined to 31% by day 30.
• VRE positivity was associated with reduced alpha diversity (median Shannon 1.90 vs 2.64; P < .01) and higher Enterococcus relative abundance (median 38% vs 0.01%; P < .01).
• Enterococcus dominance and alpha diversity largely returned toward baseline by ICU day 30.

Clinical Implications

Highlights ICU day 14 as a peak risk period for VRE colonization and microbiome collapse, suggesting opportunities for decolonization, antibiotic stewardship adjustments, or microbiome-supportive strategies.

Limitations

• Single-center medical ICU cohort with modest sample size (N=90)
• 16S sequencing limits taxonomic resolution and functional inference

Future Directions

Test targeted decolonization, stewardship modifications, and microbiome-restorative strategies timed to peak colonization; integrate shotgun metagenomics and metabolomics for functional insights.