Mycobacterium tuberculosis detection by polymerase chain reaction and identification of M. tuberculosis strain

A rapid multiprimer PCR method for detection of Mycobacterium tuberculosis complex (MTC) and simultaneous identification of M. tuberculosis in clinical samples has been developed. The method is based on simultaneous amplification of two targets: a 401 bp region from the mtp40 species-specific gene sequence of M. tuberculosis and a 544 bp fragment from the RD1 genome region which is specific for MTC but absent in BCG strains. Polymerase inhibitors in this study were detected by internal control in each test. Detection sensitivity was 25 copies of M. tuberculosis genomic DNA. Seven methods for isolation of mycobacterial DNA were compared and the technique with chloroform extraction was selected as the most efficient. The proposed method was used for analysis of 37 clinical samples and the results were compared with the results of culturing, acid-fast bacilli staining, and clinical diagnosis. The method proved to be sufficiently sensitive and specific for detection of mycobacterial DNA. Moreover, in countries with only two main pathogenic species of MTC circulating (M. tuberculosis and M. bovis) this method can be used for differentiation of these two species.