Phenotypic & genotypic characterization of vancomycin resistant Enterococcus isolates from clinical specimens.

Area of Science:

• Microbiology
• Infectious Diseases
• Clinical Research

Background:

• Enterococci are significant nosocomial pathogens.
• Increasing antimicrobial resistance, particularly to vancomycin, complicates treatment.
• Vancomycin-resistant Enterococcus (VRE) poses a critical challenge in healthcare settings.

Purpose of the Study:

• To conduct a phenotypic and genotypic characterization of VRE isolates.
• To identify vancomycin resistance genes in clinical samples from a tertiary care hospital in southern India.

Main Methods:

• Collected and tested 367 Enterococcus isolates over one year.
• Determined minimum inhibitory concentrations (MICs) for vancomycin and teicoplanin using agar dilution.
• Performed multiplex polymerase chain reaction (PCR) for genotypic analysis of vancomycin resistance genes.

Main Results:

• 32 out of 367 isolates (8.7%) were identified as VRE.
• The VanA gene was the most prevalent genotype and phenotype associated with vancomycin resistance.
• Observed heterogeneity in vanA gene clusters and co-existence of vanA and vanC1 genes in E. gallinarum.

Conclusions:

• Enterococcus species are significant nosocomial pathogens in the study population.
• The prevalence of VRE (8.7%) was high compared to other Indian studies.
• VanA is the predominant mechanism for glycopeptide resistance, with observed genotypic and phenotypic diversity in VRE.