Bacteriocin production facilitates nosocomial emergence of vancomycin-resistant Enterococcus faecium

Area of Science:

• Microbiology
• Genomics
• Epidemiology

Background:

• Vancomycin-resistant Enterococcus faecium (VREfm) is a major healthcare-associated pathogen.
• Gastrointestinal colonization by VREfm can lead to severe bloodstream infections with high mortality.
• Understanding VREfm population dynamics in hospitals is crucial for infection control.

Purpose of the Study:

• To investigate temporal changes in hospital-adapted VREfm populations.
• To identify factors driving the emergence and persistence of VREfm strains in healthcare settings.
• To compare local VREfm evolution with global trends.

Main Methods:

• Whole-genome sequencing of 710 clinical VREfm isolates from 2017-2022.
• Comparative genomic analysis with 15,631 publicly available VREfm genomes.
• Functional analysis to identify strain-specific adaptive features.

Main Results:

• The VREfm population was polyclonal, with 46% of isolates forming genetically related clusters, indicating high transmission.
• A significant shift in VREfm lineage replacement was observed both locally and globally over a 20-year period.
• Antimicrobial peptide bacteriocin T8 was identified as a potential driver for VREfm strain emergence and persistence.

Conclusions:

• Hospital-adapted VREfm populations undergo substantial temporal shifts in lineage composition.
• Bacteriocin T8 may play a critical role in the success of specific VREfm strains within the hospital environment.
• These findings have implications for developing targeted interventions against VREfm transmission and infection.