Evaluation of the frequency of phenotype and genotype of Van A and Van B genes in vancomycine resistant enterococcus isolated from clinical sample of Alzahra Hospitals in Isfahan

Enterococcis are a part of the normal flora of the human gastrointestinal tract, and play an important role in the spread of resistance genes and produce antibiotic-resistant strains. With increasing the use of vancomycin antibiotics, Vancomycin-resistant enterococci (VRE) are one of the major nosocomial pathogens in worldwide. The aim of this study was to investigate the frequency of phenotype and genotype of van genes in vancomycine resistant Enterococci. In this cross-sectional descriptive study, after isolating and identifying 165 strains of enterococci from clinical specimens in different wards of Alzahra hospital, the enterococcus isolates were identified by biochemical confirmation tests. Resistance of each isolate to vancomycin determined by disk diffusion and E-Test method and was tested for the presence of the van A and van B genes by Real time PCR. The results of the 165 isolates of enterococci collected from clinical specimens showed 79 (48%) enterococcus was resistant by disk diffusion method to vancomycin, but using E-test, only 40 (25%) enterococci was resistant in high level to vancomycin. Real-time-PCR assay of 40 samples showed 37 patients (92/5%) included Van A gene and 3 (7/5%) with Van B gene. Based on the results of the present study, the rate of isolation of Van A-containing strains was higher than that of Van B-containing of Alzahra Hospital in Isfahan. Real Time-PCR has a high specificity compared to other phenotypic methods E-Test and disk diffusion method.