Absolute and relative real-time PCR in the quantification of tst gene expression among methicillin-resistant Staphylococcus aureus: Evaluation by two mathematical models

V. Chini, A. Foka, G. Dimitracopoulos, I. Spiliopoulou

Research output: Contribution to journalArticle

31 Citations (Scopus)


Aim: Absolute and relative quantitative real-time reverse transcriptase polymerase chain reaction (RT-PCR) by the use of two mathematical models were applied in order to study the expression of tst gene encoding the toxic shock syndrome toxin-1 (TSST-1), among methicillin-resistant Staphylococcus aureus (MRSA). Methods and Results: Thirteen epidemic MRSA belonging to different clones and carrying a variety of toxin genes were selected. tst gene expression was achieved by using absolute and relative quantitative real-time RT-PCR and the SYBR® Green I. Absolute RT-PCR showed a statistically significant higher level of tst expression among strains isolated from soft tissue infections. Relative quantification was performed in relation to 23S rRNA expression by the application of two mathematical models, the 2-ΔΔCt and the Pfaffl analysis methods. Conclusions: tst gene expression was best calculated by the relative real-time RT-PCR analysis applying the Pfaffl analysis method, taking into account the reactions' efficiencies. Level of tst expression was related to patients' infection and did not depend on the MRSA genetic profile. Significance and Impact of the Study: The results indicate that the application of the Pfaffl analysis method in the evaluation of relative real-time RT-PCR is more adequate.

Original languageEnglish
Pages (from-to)479-484
Number of pages6
JournalLetters in Applied Microbiology
Issue number5
Publication statusPublished - Nov 2007
Externally publishedYes



  • Absolute and relative real-time RT-PCR
  • MRSA
  • Quantification
  • SYBR® Green I
  • tst expression

ASJC Scopus subject areas

  • Applied Microbiology and Biotechnology
  • Water Science and Technology
  • Fluid Flow and Transfer Processes
  • Microbiology
  • Ecology

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