Korean J Clin Microbiol.  2011 Dec;14(4):138-143. 10.5145/KJCM.2011.14.4.138.

Evaluation of a Newly Developed Multiplex Real-time PCR Assay for the Detection of Vancomycin-Resistant Enterococci from Rectal Swabs

• Jung MK
• Lee WG
• Park MH

• KMID: 1476035
• DOI: http://doi.org/10.5145/KJCM.2011.14.4.138

Abstract

BACKGROUND
Asymptomatic vancomycin-resistant enterococci (VRE) colonization precedes infection. VRE-colonized patients serve as silent reservoirs of enterococci that go on to colonize other patients. Rapidly identifying colonized patients is crucial to prevent the spread of VRE. The culture-based method of VRE screening is time-consuming. We evaluated the diagnostic performance of a recently developed multiplex real-time PCR for the detection of VRE.
METHODS
We obtained 105 rectal swabs from patients who were being monitored for carriage of VRE. After 24 hour incubation of swabs in enterococcosel broth (EB) supplemented with 6 microg/mL vancomycin, multiplex real-time PCR was performed using the Anyplex(TM) VanR Real-time Detection (VanR) kit (Seegene, Inc., Seoul, Korea). The results of multiplex real-time PCR were compared to those of culture. We evaluated the specificity and detection limits of multiplex real-time PCR using VanR for VRE.
RESULTS
A total of 96/105 (91.4%) samples were VRE positive according to multiplex real-time PCR with EB while 85/105 (80.9%) samples were positive in culture. Eleven discordant results (10.4%) (multiplex real-time PCR positive, culture negative) were noted. All non-enterococcal bacteria and vancomycin-susceptible enterococci were negative. The DNA detection limits of VanR were 0.035 pg per reaction (3 microL) for Enterococcus faecium and 0.35 pg for Enterococcus faecalis.
CONCLUSION
The application of multiplex real-time PCR after EB incubation allows rapid and sensitive detection in 26-28 hours for VRE screening from rectal swabs. This method could facilitate the timely implementation of contact isolation to prevent the spread of VRE.

Keyword

Vancomycin resistant enterococci; Multiplex real-time PCR; Rectal swab

MeSH Terms

Bacteria
Colon
DNA
Enterococcus
Enterococcus faecium
Humans
Limit of Detection
Mass Screening
Real-Time Polymerase Chain Reaction
Sensitivity and Specificity
Vancomycin
DNA
Vancomycin

Figure

• 

  Fig. 1. Results of multiplex realtime PCR for the detection of VRE in triplicate. (A) E. faecalis (ATCC 29212). (B) E. faecium (BM 4147, vanA). (C) E. faecalis (ATCC 51299, vanB).

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