Phenotypic and genetic characteristics of vancomycin-resistant Enterococcus faecium

Area of Science:

• Microbiology
• Genomics
• Infectious Diseases

Background:

• Vancomycin-resistant Enterococcus faecium (VREfm) poses a significant clinical challenge due to its multidrug resistance.
• Understanding the genetic basis and population structure of VREfm is critical for effective infection control.

Purpose of the Study:

• To characterize the antimicrobial resistance profiles and molecular epidemiology of VREfm strains from clinical specimens.
• To identify the specific genes conferring resistance to tetracycline, gentamicin, and streptomycin.
• To discover novel sequence types (STs) within the VREfm population.

Main Methods:

• Susceptibility testing and resistance gene amplification were performed on 43 VREfm clinical isolates.
• Multilocus sequence typing (MLST) was used to determine the clonal complex and sequence types.
• Whole-genome analysis was conducted on selected strains to confirm resistance genes.

Main Results:

• All 43 VREfm strains exhibited multidrug resistance and the VanA phenotype, belonging to clonal complex (CC17).
• ST17 and ST78 were the predominant sequence types; ST1392 and ST1394 were identified as novel STs.
• Genes tet(O), tet(K), acc(6')-Ie-aph(2')-Ia, and aad(6) were identified as responsible for tetracycline, gentamicin, and streptomycin resistance, respectively.
• Significant genomic variation was observed among the strains.

Conclusions:

• The study highlights the genetic diversity and specific resistance mechanisms within VREfm clinical isolates.
• Identification of novel STs and resistance genes provides valuable insights for VREfm surveillance and treatment strategies.
• The extensive genomic variation underscores the importance of continuous monitoring for effective prevention and control of VREfm infections.