Genetic characterization of a VanG-type vancomycin-resistant Enterococcus faecium clinical isolate

Area of Science:

• Microbiology
• Genomics
• Antimicrobial Resistance

Background:

• Enterococcus faecium is a significant opportunistic pathogen.
• Vancomycin resistance in enterococci (VRE) poses a major therapeutic challenge.
• The vanG operon is a known mechanism of vancomycin resistance.

Observation:

• A clinical E. faecium 16-346 isolate was characterized phenotypically and genotypically.
• Whole genome sequencing revealed the vanG operon integrated into a mobile genetic element.
• Vancomycin resistance was not transferable via filter mating.

Findings:

• The E. faecium 16-346 isolate exhibited resistance to vancomycin (MIC 8 mg/L) and other antibiotics.
• The vanG operon was located on the chromosome within a mobile genetic element.
• Expression of the vanG operon was found to be inducible by vancomycin.

Implications:

• This is the first report of a VanG-type vancomycin-resistant E. faecium.
• The findings underscore the continuous evolution of resistance mechanisms in E. faecium.
• This discovery contributes to understanding the spread of antimicrobial resistance.