Related Experiment Video
Updated: May 1, 2026
Methodology for the Study of Horizontal Gene Transfer in Staphylococcus aureus
Published on: March 10, 2017
Protracted transmission and persistence of ST80 vancomycin-resistant Enterococcus faecium clonal complex types
N L Kavanagh1, P M Kinnevey1, S A Egan1
1Microbiology Research Unit, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Dublin, Ireland.
Background:
Vancomycin-resistant Enterococcus faecium (VREfm) are significant nosocomial pathogens. Sequence type (ST) 80 vanA-encoding VREfm predominate in Irish hospitals, but their transmission is poorly understood.
Aims:
To investigate transmission and persistence of predominant complex type (CT) VREfm in two wards of an Irish hospital (H1) using whole-genome sequencing, and their intra- and inter-hospital dissemination.
Methods:
Rectal screening (N = 330, September 2019 to December 2022) and environmental (N = 48, November 2022 to December 2022) E. faecium were investigated. Isolate relatedness was assessed by core-genome multi-locus sequence typing (cgMLST) and core-genome single nucleotide polymorphism (cgSNP) analysis. Likely transmission chains were identified using SeqTrack (https://graphsnp.fordelab.com/graphsnp) using cgSNP data and recovery location. Well-characterized E. faecium (N = 908) from seven Irish hospitals including H1 (June 2017 to July 2022) were also investigated.
Findings:
Conventional MLST assigned isolates to nine STs (ST80, 82%). cgMLST identified three predominant ST80 CTs (CT2933, CT2932 and CT1916) (55% of isolates) of related isolates (≤20 allelic differences). cgSNP analysis differentiated these CTs into multiple distinct closely related genomic clusters (≤10 cgSNPs). Parisimonious network construction identified 55 likely inter- and intra-ward transmissions with epidemiological support between patients ≤30 days involving 73 isolates (≤10 cgSNPs) from seven genomic clusters. Numerous other likely transmissions over longer time periods without evident epidemiological links were identified, suggesting persistence and unidentified reservoirs contribute to dissemination. The three CTs predominated among E. faecium (N = 1286) in seven hospitals, highlighting inter-hospital spread without known epidemiological links.
Conclusion:
This study revealed the long-term intra- and inter-hospital dominance of three major CT ST80 VREfm lineages, widespread transmission and persistence, implicating unidentified reservoirs.
Insights
Vancomycin-resistant Enterococcus faecium (VREfm) ST80 lineages dominate Irish hospitals, spreading widely within and between facilities. Unidentified reservoirs likely contribute to VREfm persistence and transmission, highlighting a significant public health challenge.
Area of Science:
- Microbiology
- Genomics
- Epidemiology
Background:
- Vancomycin-resistant Enterococcus faecium (VREfm) are critical healthcare-associated pathogens.
- Sequence type (ST) 80 VREfm are prevalent in Irish hospitals, but transmission dynamics remain unclear.
Purpose of the Study:
- To investigate the transmission and persistence of dominant VREfm complex types (CTs) in an Irish hospital.
- To analyze the intra- and inter-hospital dissemination of VREfm using whole-genome sequencing.
Main Methods:
- Whole-genome sequencing (WGS) including core-genome multi-locus sequence typing (cgMLST) and core-genome single nucleotide polymorphism (cgSNP) analysis.
- Investigation of rectal and environmental Enterococcus faecium isolates.
- Network construction using SeqTrack to identify transmission chains.
Main Results:
- Three ST80 VREfm complex types (CTs) predominated, with cgSNP analysis revealing distinct genomic clusters.
- Fifty-five likely inter- and intra-ward transmissions were identified within 30 days, alongside evidence of longer-term persistence.
- These dominant CTs were prevalent across seven Irish hospitals, indicating significant inter-hospital spread.
Conclusions:
- Three major ST80 VREfm lineages exhibit long-term dominance and widespread transmission within and between hospitals.
- Persistence of VREfm is likely driven by unidentified reservoirs, complicating control efforts.
- Genomic surveillance is crucial for understanding and managing VREfm outbreaks.
More Related Videos
08:58Isolation and Identification of Waterborne Antibiotic-Resistant Bacteria and Molecular Characterization of their Antibiotic Resistance Genes
Published on: March 3, 2023
06:56Detection of Horizontal Gene Transfer Mediated by Natural Conjugative Plasmids in E. coli
Published on: March 24, 2023
Related Concept Videos
01:30Development of Antibiotic Resistance
01:25Mechanism of Antibiotic Resistance in MRSA
01:25Clinical Significance of Antibiotic Resistance