Virulence and antimicrobial resistance in clinical Enterococcus faecium

Area of Science:

• Microbiology
• Infectious Diseases
• Clinical Science

Background:

• Enterococcus faecium is a significant cause of hospital-acquired infections.
• Virulence factors and antibiotic resistance patterns are crucial for understanding E. faecium pathogenicity.
• Monitoring these traits in clinical isolates is essential for effective treatment strategies.

Purpose of the Study:

• To determine the prevalence of seven virulence determinants in E. faecium blood isolates over six years.
• To investigate the correlation between specific virulence genes and antibiotic resistance profiles.

Main Methods:

• Polymerase chain reaction (PCR) was used to screen for virulence genes: asa1, cylA, ace, efaA(fs), esp(fm), gelE, and hyl(fm).
• Antibiotic susceptibility testing, including MIC determination for ampicillin, ciprofloxacin, gentamicin, imipenem, linezolid, vancomycin, and daptomycin, was performed.
• Statistical analysis was employed to assess correlations between virulence factors and resistance.

Main Results:

• The enterococcal surface protein (esp(fm)) gene was detected in 56% of isolates; hyaluronidase (hyl(fm)) in 4%. Other genes were rare (<1%).
• High rates of antibiotic resistance were observed: 77% to ampicillin, 90% to ciprofloxacin, and 83% to imipenem.
• A significant association (P<0.01) was found between esp(fm) presence and resistance to ampicillin, ciprofloxacin, and imipenem.

Conclusions:

• The esp(fm) gene is a common virulence factor in E. faecium blood isolates.
• The presence of esp(fm) is strongly linked to multidrug resistance in these isolates.
• These findings highlight the importance of esp(fm) as a potential marker for antibiotic resistance in E. faecium infections.