Cloning of a gene from Mycobacterium tuberculosis coding for a hypothetical 27 kDa protein and its use for the specific PCR identification of these mycobacteria

PCR targeting the IS6110 has been considered specific for identification of Mycobacterium tuberculosis and is frequently applied to confirm the presen ce of this organism directly in biological specimens. However, several auth ors found that some M. tuberculosis strains failed to hybridize with the IS 6110 probe and other authors found that false-positive results may be obtai ned for clinical samples when some methods based on IS6110 are used. In the present study, the p27 gene isolated from a cosmid library was found to be highly specific for M. tuberculosis complex strains and allowed us to deve lop a PCR-based assay for rapid detection and identification of this mycoba cterium. One pair of primers and two oligonucleotide probes were successful ly used to amplify and to detect the DNA of strains belonging to the M. tub erculosis complex. These primers and probes did not hybridize with DNA from any of the 21 other mycobacterial species tested. It is worth noting that the chosen primers and probes hybridize with DNA from the M. tuberculosis s train with no IS6110, furthermore no strain without p27 was found among the 410 strains tested in the present study. (C) 2000 Academic Press.