title: Evaluation of the iNtRON VRE vanA/vanB real-time PCR assay for detection of vancomycin-resistant enterococci.
abstract: BACKGROUND
  Recently, the iNtRON VRE vanA/vanB real-time PCR (iNtRON; iNtRON Biotechnology, Korea) assay, a multiplex real-time PCR method, was introduced. In this prospective study, we compared the iNtRON assay with the Seeplex VRE ACE detection kit (Seeplex; Seegene, Korea), a conventional multiplex PCR assay.
  
  
  METHODS
  A chromogenic agar-based culture, in which pre-selected vancomycin-resistant enterococci (VRE) was grown and subsequently plated on blood agar with vancomycin disks, was regarded as the reference method. A total of 304 consecutive rectal swab specimens were tested for VRE by culture and by iNtRON and Seeplex PCR assays. For the PCR assays, specimens were enriched for 16-24 hr before PCR.
  
  
  RESULTS
  VRE were isolated from 44 (14.5%) specimens by chromogenic agar-based culture. The clinical sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the iNtRON assay were 100% (95% confidence interval: 89.8%-100%), 99.2% (96.9%-99.9%), 95.6% (83.6%-99.2%), and 100% (98.2%-100%), respectively, while those of the Seeplex assay were 97.7% (86.2%-99.9%), 99.6% (97.5%-99.9%), 97.7% (86.2%-99.9%), and 99.6% (97.5%-99.9%), respectively. The iNtRON assay had a detection limit of 3,159 copies/µL and 13,702 copies/µL for the vanA and vanB genes, respectively. No cross-reactivity was observed in 11 non-VRE bacterial culture isolates.
  
  
  CONCLUSIONS
  The overall performance of the iNtRON assay was comparable to that of a chromogenic agar-based culture method for prompt identification of VRE-colonized patients in hospitals. This assay could be an alternative or supportive method for the effective control of nosocomial VRE infection.
authors.affiliation: Department of Laboratory Medicine and Genetics, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Hee Jae
authors.initials: HJ
authors.lastname: Huh
authors.affiliation: Department of Laboratory Medicine and Genetics, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Mi-Ae
authors.initials: MA
authors.lastname: Jang
authors.affiliation: Department of Laboratory Medicine, Gachon University Gil Hospital, Incheon, Korea.
authors.forename: Ja Young
authors.initials: JY
authors.lastname: Seo
authors.affiliation: Center for Clinical Medicine, Samsung Biomedical Research Institute, Samsung Medical Center, Seoul, Korea.
authors.forename: Ji-Youn
authors.initials: JY
authors.lastname: Kim
authors.affiliation: Department of Laboratory Medicine and Genetics, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Chang-Seok
authors.initials: CS
authors.lastname: Ki
authors.affiliation: Department of Laboratory Medicine and Genetics, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Jong-Won
authors.initials: JW
authors.lastname: Kim
authors.affiliation: Department of Laboratory Medicine and Genetics, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Nam Yong
authors.initials: NY
authors.lastname: Lee
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D015373:Bacterial Typing Techniques / Q000379:methods* / Q000592:standards; D019729:Carbon-Oxygen Ligases / Q000235:genetics*; D004269:DNA, Bacterial / Q000378:metabolism*; D016908:Gram-Positive Bacterial Infections / Q000382:microbiology; D006801:Humans; D011933:Reagent Kits, Diagnostic; D060888:Real-Time Polymerase Chain Reaction; D020713:Vancomycin Resistance / Q000235:genetics; D065507:Vancomycin-Resistant Enterococci / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D011933:Reagent Kits, Diagnostic; C071437:VanA ligase, Bacteria; C079913:VanB protein, Enterococcus; D019729:Carbon-Oxygen Ligases
keywords: Performance; Real-time PCR; Vancomycin-resistant enterococci; vanA; vanB