Gut Microbiota Predict Enterococcus Expansion but Not Vancomycin-Resistant Enterococcus Acquisition.

Area of Science:

• Microbiology
• Hospital-acquired infections
• Gut microbiome

Background:

• Vancomycin-resistant Enterococcus (VRE) is a significant cause of hospital-acquired infections.
• Gut microbiota's role in VRE acquisition remains unclear, despite its known role in colonization resistance.
• Understanding VRE acquisition pathways is crucial for effective infection control.

Purpose of the Study:

• To investigate the association between gut microbiota composition and VRE acquisition in hospitalized patients.
• To determine if baseline gut microbiome profiles can predict VRE colonization.

Main Methods:

• A case-control study design was employed, matching VRE-colonized patients (cases) with non-colonized patients (controls).
• 16S rRNA gene amplicon sequencing was used to characterize gut bacterial communities from rectal swab specimens.
• Analysis included 236 samples from 59 matched case-control pairs, considering risk factors and 'time at risk'.

Main Results:

• No significant differences in gut microbiota diversity or composition were observed between cases and controls at baseline.
• Post-hospitalization, only the abundance of Enterococcus-containing operational taxonomic units (OTUs) differed significantly between groups (P=0.01).
• Presence of Blautia spp. on admission was associated with lower Enterococcus abundance after VRE colonization (P=0.004).

Conclusions:

• The baseline gut microbiome 16S profile does not predict VRE acquisition in hospitalized patients, likely due to dynamic microbiota changes.
• VRE acquisition and subsequent Enterococcus dominance appear to be distinct processes.
• Specific baseline gut bacteria, such as Blautia and Lactobacillus, may influence Enterococcus expansion post-colonization.