Linezolid vancomycin resistant Enterococcus isolated from clinical samples in Tehran hospitals

Area of Science:

• Microbiology
• Infectious Diseases
• Antimicrobial Resistance

Background:

• Vancomycin-resistant enterococci (VRE) represent a significant and increasing healthcare threat.
• Limited therapeutic choices necessitate the development and monitoring of new antimicrobial agents.
• Emergence of VRE strains necessitates surveillance of antimicrobial susceptibility patterns.

Purpose of the Study:

• To determine the prevalence of different enterococcal species.
• To assess the antimicrobial resistance patterns of enterococci isolates.
• To investigate resistance to vancomycin, teicoplanin, and linezolid in specific hospital settings.

Main Methods:

• Collected 200 enterococcal isolates from various clinical sources (urine, blood, stool, wound) over 14 months.
• Utilized disk diffusion and agar dilution methods for antibiotic susceptibility testing.
• Tested isolates against vancomycin, teicoplanin, and linezolid.

Main Results:

• Identified vancomycin resistance in 8.5% of isolates, teicoplanin resistance in 3%, and linezolid resistance in 2%.
• Among vancomycin-resistant enterococci (VRE), vanA, vanB, and vanC genotypes were detected in 35.2%, 25%, and 5.88% of isolates, respectively.
• Four VRE isolates (23.5%) exhibited linezolid resistance, with minimum inhibitory concentrations (MICs) ranging from 16 to 32 µg/mL. Two of these were Enterococcus faecium.

Conclusions:

• Vancomycin resistance is prevalent in enterococci, with specific genotypic patterns identified.
• Emerging resistance to linezolid among VRE isolates is a critical concern.
• The presence of linezolid-resistant VRE, particularly Enterococcus faecium, highlights the need for ongoing surveillance and infection control measures.