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Open Access Highly Accessed Research article

Evaluation of five DNA extraction methods for purification of DNA from atherosclerotic tissue and estimation of prevalence of Chlamydia pneumoniae in tissue from a Danish population undergoing vascular repair

Tina Mygind1*, Lars Østergaard2, Svend Birkelund1, Jes S Lindholt3 and Gunna Christiansen1

Author affiliations

1 Department of Medical Microbiology and Immunology, Wilhelm Meyers Allé, The Bartholin Building, University of Aarhus, DK-8000 Aarhus C, Denmark

2 Research Unit Q, Department of Infectious Diseases, Skejby Hospital, University Hospital of Aarhus, Brendstrupgaardsvej, DK-8200 Aarhus N, Denmark

3 Department of Vascular Surgery, Viborg Hospital, Viborg, Denmark

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Citation and License

BMC Microbiology 2003, 3:19  doi:10.1186/1471-2180-3-19

Published: 2 September 2003

Abstract

Background

To date PCR detection of Chlamydia pneumoniae DNA in atherosclerotic lesions from Danish patients has been unsuccessful. To establish whether non-detection was caused by a suboptimal DNA extraction method, we tested five different DNA extraction methods for purification of DNA from atherosclerotic tissue.

Results

The five different DNA extraction methods were tested on homogenate of atherosclerotic tissue spiked with C. pneumoniae DNA or EB, on pure C. pneumoniae DNA samples and on whole C. pneumoniae EB. Recovery of DNA was measured with a C. pneumoniae-specific quantitative real-time PCR. A DNA extraction method based on DNA-binding to spin columns with a silica-gel membrane (DNeasy Tissue kit) showed the highest recovery rate for the tissue samples and pure DNA samples. However, an automated extraction method based on magnetic glass particles (MagNA Pure) performed best on intact EB and atherosclerotic tissue spiked with EB. The DNeasy Tissue kit and MagNA Pure methods and the highly sensitive real-time PCR were subsequently used on 78 atherosclerotic tissue samples from Danish patients undergoing vascular repair. None of the samples were positive for C. pneumoniae DNA. The atherosclerotic samples were tested for inhibition by spiking with two different, known amounts of C. pneumoniae DNA and no samples showed inhibition.

Conclusion

As a highly sensitive PCR method and an optimised DNA extraction method were used, non-detection in atherosclerotic tissue from the Danish population was probably not caused by use of inappropriate methods. However, more samples may need to be analysed per patient to be completely certain on this. Possible methodological and epidemiological reasons for non-detection of C. pneumoniae DNA in atherosclerotic tissue from the Danish population are discussed. Further testing of DNA extraction methods is needed as this study has shown considerable intra- and inter-method variation in DNA recovery.

Keywords:
Chlamydia pneumoniae; atherosclerotic tissue; DNA extraction; real-time PCR