Annals of Clinical Microbiology, The official Journal of the Korean Society of Clinical Microbiology

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Indexed in KCI, KoreaMed, Synapse, DOAJ
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pISSN 2288-0585 eISSN 2288-6850

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

Original article

Annals of Clinical Microbiology (Ann Clin Microbiol) 2011 December, Volume 14, Issue 4, pages 138-143.

https://doi.org/10.5145/ACM.2011.14.4.138

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

Min-Kwon Jung1, Wee-Gyo Lee2, Myung-Hwa Park2
Department of Laboratory Medicine, 1Seran General Hospital, Seoul, 2Ajou University School of Medicine, Suwon, Korea

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 μg/mL vancomycin, multiplex real-time PCR was performed using the AnyplexTM 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 μL) 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. (Korean J Clin Microbiol 2011;14: 138-143)

Keywords

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