RAPID DETECTION OF MYCOBACTERIUM-TUBERCULOSIS IN CLINICAL-SAMPLES BY POLYMERASE CHAIN-REACTION

A polymerase chain reaction for the rapid and specific detection of My cobacterium tuberculosis has been used and evaluated for clinical appl icability. Two oligonucleotide primers derived from the nucleotide seq uence of a immunogenic protein MPB 64 amplified DNA from M. tuberculos is and M. bovis. No amplification was observed from any of ten differe nt mycobacterial strains. A total of 126 clinical samples were amplifi ed and tested by both dot blot hybridization and restriction enzyme an alysis. M. tuberculosis was detected by PCR in 38 smear and 42 culture positive cases An additional 16 culture negative specimens mere PCR p ositive yielding an overall M. tuberculosis positivity rate of 46.0% ( 58/126) compared to 33.3% (42/126) by culture. The superior sensitivit y of PCR to culture was more evident in non-pulmonary cases where PCR picked up 10 cases in addition to 6 culture positives out of 46 specim ens. On the other hand, out of 80 pulmonary specimens only 6 cases in addition to 36 culture positives mere picked up by PCR. The specificit y of PCR was confirmed with dot blot hybridization and restriction enz yme analysis. This study corroborates that PCR offers a more sensitive and rapid alternative for the detection of M. tuberculosis to culture , and that it can be used in uncultured clinical specicimens.