Ann Lab Med.  2015 Jan;35(1):76-81. 10.3343/alm.2015.35.1.76.

Evaluation of the iNtRON VRE vanA/vanB Real-Time PCR Assay for Detection of Vancomycin-Resistant Enterococci

• Huh HJ
• Jang MA
• Seo JY
• Kim JY
• Ki CS
• Kim JW
• Lee NY

• KMID: 2363151
• DOI: http://doi.org/10.3343/alm.2015.35.1.76

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/microL and 13,702 copies/microL 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.

Keyword

Real-time PCR; Performance; vanA; vanB; Vancomycin-resistant enterococci

MeSH Terms

Bacterial Proteins/*genetics
Bacterial Typing Techniques/*methods/standards
Carbon-Oxygen Ligases/*genetics
DNA, Bacterial/*metabolism
Gram-Positive Bacterial Infections/microbiology
Humans
Reagent Kits, Diagnostic
*Real-Time Polymerase Chain Reaction
Vancomycin Resistance/genetics
Vancomycin-Resistant Enterococci/*genetics/isolation & purification
Bacterial Proteins
Carbon-Oxygen Ligases
DNA, Bacterial
Reagent Kits, Diagnostic

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