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Clinical and Diagnostic Laboratory Immunology, March 2001, p. 279-282, Vol. 8, No. 2
Institut für Allgemeine Hygiene und
Umwelthygiene, Universität Tübingen,
Tübingen,1 and 4Base Lab GmbH
Advanced Molecular Analysis, Reutlingen,2
Germany
Received 8 August 2000/Returned for modification 3 November
2000/Accepted 27 November 2000
Bacteria have evolved sophisticated regulatory circuits to modulate
their gene expression in response to disparate environments. In order
to monitor bacterial gene expression and regulation in the host,
methods for direct transcript analysis from clinical specimens are
needed. For most bacterial infections, amplification of the mRNAs of
interest is necessary due to the low numbers of cells present and the
low levels of specific transcripts. Here we compare two methods of
quantitative reverse transcription-PCR (RT-PCR)
1071-412X/01/$04.00+0 DOI: 10.1128/CDLI.8.2.279-282.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.
Quantification of Bacterial Transcripts during
Infection Using Competitive Reverse Transcription-PCR (RT-PCR) and
LightCycler RT-PCR
competitive RT-PCR
using a one-tube system followed by standard gel analysis and the
real-time detection of PCR product formation by fluorescence resonance
energy transfer technology using the LightCycler unit. We isolated
Staphylococcus aureus RNA directly from clinical specimens
obtained from cystic fibrosis patients with chronic S. aureus lung infection and from an animal model of foreign-body
infection with no further cultivation of the bacteria. Competitive
RT-PCR and LightCycler RT-PCR were tested for their ability to quantify
the transcription of a constitutively expressed gyrase gene
(gyr) and a highly regulated
-toxin gene (hla) of S. aureus. Reproducible results were
obtained with both methods. A sensitivity of 104
(gyr) and 103 (hla) copies,
respectively, was reached, which was sufficient for the quantification
of transcripts during bacterial infection. Overall, the competitive
RT-PCR is a robust technique which does not need special RNA
purification. On the negative side, it is labor intensive and time
consuming, thus limiting the numbers of samples which can be analyzed
at a given time. LightCycler RT-PCR is very susceptible to even traces
of inhibitors, but it allows high-throughput processing of samples.
*
Corresponding author. Mailing address: Institut
für Allgemeine Hygiene und Umwelthygiene, Universität
Tübingen, Wilhelmstrasse 31, 72074 Tübingen, Germany.
Phone: 49-7071-2980187. Fax: 49-7071-293011. E-mail:
christiane.wolz{at}uni-tuebingen.de.
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