Volume 5 Supplement 6

International Conference on Prevention & Infection Control (ICPIC 2011)

Open Access

Quantitative PCR for etiologic diagnosis of methicillin-resistant Staphylococcus aureus pneumonia in intensive care unit

  • T Jeon1,
  • D Seo1,
  • SJ Kwon2 and
  • J Kang3
BMC Proceedings20115(Suppl 6):P66

DOI: 10.1186/1753-6561-5-S6-P66

Published: 29 June 2011

Introduction / objectives

Because methicillin-resistant Staphylococcus aureus (MRSA) was frequent pathogen in ventilator-associated pneumonia (VAP), the rapid identification of it from respiratory samples was important. Therefore, our aim was to evaluate the utility of qPCR as a useful method for etiologic diagnoses of MRSA-based pneumonia.


We performed qPCR for mecA, S. aureus-specific femA-SA and S. epiderdimis-specific femA-SE genes from bronchoalvolar lavage (BAL) or bronchial washing samples obtained from clinical suspected VAP. We spiked an internal control (SPUD) at in the course of DNA extraction. We estimated colony forming units (CFU/ml) of MRSA samples through a standard curve of a serially diluted reference MRSA strain. We compared threshold cycle (Ct) value of MRSA of clinical samples with the microbiologic culture results of that.


We examined 72 samples of 64 patients with clinical suspected VAP. We obtained the mecA gene standard curve. It showed that the detection limit of the mecA gene was 100fg, which corresponded to a copy number of 30. We chose cut-off Ct values of 27.94 (equivalent to 1 × 104 CFU/ml) and 21.78 (equivalent to 1 × 105 CFU/ml). Using these cut-off values, the sensitivity and specificity of our assay was 88.9% and 88.9%, respectively, when compared with quantitative cultures.


Our results were valuable for diagnosing and identifying pathogen for VAP. We suggest that our modified qPCR method is an appropriate and rapid tool for diagnosing of clinical pathogens in intensive care unit (ICU) patients.

Disclosure of interest

None declared.

Authors’ Affiliations

Medical School of Konyang, Konyang University
Department of Internal Medicine, Konyang University Hospital
College of Medicine, Konyang University


© Jeon et al; licensee BioMed Central Ltd. 2011

This article is published under license to BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.