Abstract:Objective To investigate the possibility of using DNA extracts from patients sputum smears to detect the multidrug-resistant Mycobacterium tuberculosis (MDRTB).Methods Totally 18 isolates of M. tuberculosis were collected from three hospitals and their resistance to rifampin were detected. After PCR the rpoB gene from cultured strains DNA and DNA extracts from stained slides,identification of mutant rpoB gene was performed by hybridization using line probe assay and DNA sequencing.Results Among the 18 isolates, 12 were resistant to rifampin. In 12 resistant strains,analysis of the rpoB gene mutant revealed that DNA samples from the cultures were 100% (12/12),whereas that from sputums were 91.7% (11/12). Sequence analysis of the rpoB mutants DNA extracts rifampin-resistant M. tuberculosis carried altered codons within the core region of the rpoB gene.Conclusion Molecular diagnosis method of the rpoB gene mutant in M. tuberculosis DNA directly extracted from stained sputum slides could provide simple method for the clinical laboratory..