Genotypic Characterization of Vancomycin-Resistant Enterococcus spp. In Tertiary Center, Iran

Area of Science:

• Clinical microbiology
• Molecular epidemiology
• Antimicrobial resistance

Background:

• Rising rates of enterococci infections and antimicrobial resistance globally.
• Vancomycin-resistant enterococci (VRE) pose a significant threat in healthcare settings.
• Genetic variations in VRE influence antibiotic susceptibility and treatment strategies.

Purpose of the Study:

• To investigate antimicrobial resistance patterns in VRE.
• To determine genotypic variations among VRE isolates.
• To identify prevalent VRE genotypes and their association with resistance.

Main Methods:

• Isolation and identification of enterococci from clinical specimens.
• Antimicrobial susceptibility testing using disk diffusion.
• DNA extraction and multiplex PCR to detect vanA, vanB, vanC, vanD genes, and CC17.

Main Results:

• 235 enterococci isolates; 42% were VRE, predominantly Enterococcus faecium (91.1%).
• All VRE isolates harbored the vanA gene; vanB, vanC, and vanD genes were absent.
• The clonal complex 17 (CC17) was identified in 68.3% of E. faecium isolates.

Conclusions:

• The vanA gene is the predominant genotype among VRE in the study region.
• Enterococcus faecium carrying the vanA gene and belonging to CC17 are common.
• Findings highlight the importance of genotypic analysis for understanding VRE epidemiology and guiding treatment.