Comparison of nine DNA extraction methods for the diagnosis of bovine tuberculosis by real time PCR.

Bovine tuberculosis is an infectious disease with a high impact on the cattle industry, particularly in developing countries. PCR is a very sensitive method for detection of infectious agents, but the sensitivity of molecular diagnosis is largely dependent on the efficiency of the DNA extraction methods. The objective of this study was to evaluate DNA extraction methods for direct detection of Mycobacterium bovis in bovine tissue. Nine commercial kits for DNA extraction were evaluated when combined with two real time PCRs. The DNeasy Blood & Tissue Kit from QIAGEN showed better performance and sensitivity followed by the DNA Mini Kit RBC and FTA Elute Micro Card. Results suggested that, even when the analytical sensitivity of the qPCR is very high, the extraction method can influence the diagnostic sensitivity.