title: A new approach of real time polymerase chain reaction in detection of vancomycin-resistant enterococci and its comparison with other methods.
abstract: BACKGROUND
  Vancomycin-resistant enterococci (VRE) are third leading cause of nosocomial infection. Therefore, an effective, accurate and early detection of VRE along with their minimum inhibitory concentrations (MICs) is required to initiate appropriate therapy and thus better patient outcome.
  
  
  OBJECTIVE
  To detect VRE by real time quantitative polymerase chain reaction (Q-PCR) and to compare the results with chrom ID (C-ID) VRE and PCR. Further the study also determined the fold change of vanA gene by Q-PCR in different groups of VRE isolates classified on the basis of glycopeptides MIC range.
  
  
  METHODS
  A total of 145 (80 VRE and 65 vancomycin-susceptible enterococci) clinical isolates were included in the study. After the screening of VRE isolates MICs were determined by E-test and agar dilution method. Further VRE was confirmed by vanA and vanB specific PCR and Q-PCR.
  
  
  RESULTS
  The sensitivity and specificity of C-ID VRE was 100% and 95.38%. However, sensitivity and specificity of conventional and Q-PCR were found to be 100%. Conventional and Q-PCR confirmed that our all isolates were vanA type. Mean R value was significantly higher ( P < 0.001) in group I (MIC > 1024 μg/ml) when compared to group II (MIC 512-1024 μg/ml) and group III (MIC < 512 μg/ml) isolates. The mean R was also significantly higher in group II when compared to group III isolates ( P = 0.038).
  
  
  CONCLUSIONS
  Q-PCR is a rapid technique to detect vanA in enterococci along with their MIC range, thus it might be helpful to decide the treatment modalities of infections caused by VRE.
authors.affiliation: Department of Microbiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India.
authors.forename: A
authors.initials: A
authors.lastname: Tripathi
authors.forename: S K
authors.initials: SK
authors.lastname: Shukla
authors.forename: A
authors.initials: A
authors.lastname: Singh
authors.forename: K N
authors.initials: KN
authors.lastname: Prasad
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D019729:Carbon-Oxygen Ligases / Q000235:genetics; D016983:Enterococcus / Q000187:drug effects* / Q000302:isolation & purification; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*; D013997:Time Factors; D020713:Vancomycin Resistance
chemical_list: D001426:Bacterial Proteins; C071437:VanA ligase, Bacteria; C079913:VanB protein, Enterococcus; D019729:Carbon-Oxygen Ligases