Comparison of three different primer pairs for the detection of Mycobacterium tuberculosis by polymerase chain reaction in paraffin-embedded tissues.

SETTING

More than five different primer pairs have been used for the detection of Mycobacterium tuberculosis deoxyribonucleic acid (DNA) with the polymerase chain reaction (PCR).

OBJECTIVE

The sensitivity and specificity of PCR were evaluated using three different primer pairs in the detection of M. tuberculosis in paraffin-embedded tissues.

DESIGN

Thirty-eight tissue specimens from 23 patients were studied. Eighteen samples were obtained from 10 tuberculosis patients, and 20 samples obtained from 13 patients with other diseases were used as negative controls. DNA extracted from paraffin-embedded tissues was used directly for PCR amplification using primers IS1 and IS2 to amplify a 123 base pair (bp) region of IS6110, sjMT3 and sjMTr2 to amplify a 281 bp region of protein antigen b, and INS1 and INS2 to amplify a 245 bp region of IS986. Each amplification was performed double-blinded and repeated three times including positive and negative control samples.

RESULTS

IS1 and IS2 gave a positive result in each of the double samples obtained from eight tuberculosis patients and in the single samples obtained in the two others, sjMT3 and sjMTr2 detected 13 of the 18 tuberculosis samples, and INS1 and INS2 detected only three of the 18.

CONCLUSION

These results highlight the importance of selecting appropriate primers to obtain high sensitivity in detecting M. tuberculosis in paraffin-embedded tissues by PCR.