Deciphering vancomycin resistance in Enterococcus faecium: gene distribution, sequence typing, and global...

Area of Science:

• Microbiology
• Genomics
• Epidemiology

Background:

• Enterococcus faecium is a significant opportunistic pathogen.
• Vancomycin resistance in E. faecium poses a major public health threat.
• Understanding the genetic basis and spread of vancomycin resistance genes (van) is critical.

Purpose of the Study:

• To analyze the global prevalence and distribution of van genes in E. faecium.
• To investigate the genetic relationships and epidemiological characteristics of van-carrying E. faecium strains.
• To identify the most prevalent van genotypes and sequence types (STs).

Main Methods:

• Downloaded and quality-filtered 3,256 E. faecium genome sequences, retaining 2,235.
• Screened genomes for van genes using blastn.
• Determined sequence types (STs) using pubMLST profiles.

Main Results:

• 1,071 out of 2,235 (47.9%) E. faecium genomes harbored van genes.
• Eight van genotypes were identified, with vanA, vanB, vanD, and vanM accounting for 47.6%.
• ST17 was the most prevalent ST among van-carrying strains, predominantly isolated from humans in the United States, with vanA being the most common gene in 2015.

Conclusions:

• Van genes are widely distributed in E. faecium globally.
• Human populations and clinical settings show a significant prevalence of van-carrying E. faecium.
• Monitoring and intervention strategies targeting the spread of ST17 strains are essential.