SSCP technique in detection of rpoB gene mutation in rifampin resistant Mycobacterium tuberculosis

Objective To study the role of molecular biology technique in evaluating rifampin(RFP)resistance in Mycobacterium tuberculosis. Methods Primers were designed for amplifying 183 bp fragment of rpoB gene ,and 45 isolates of Mycobacteriun tuberculosis were analyzed by PCR SSCP.DNA sequencing was also performed in some of the isolates.Results To Compare the susceptibility test, 16 RFP susceptible strains and 26 RFP resistant strains were detected by SSCP. The positivity and specitivity was 93.3% and 100%,respectively. In DNA sequencing of the 183bp fragment of some strains, RFP resistant phenotype of Mycobacterium isolates experienced nucleotide changes which led to substituted aminoacid at Ser 531 and His 526 in the rpoB gene ,while RFP susceptible strains exhibited no mutations in this region. Conclusion PCR SSCP technique is a simple,rapid and accurate method and would be used to evaluate RFP resistance in Mycobacterium tuberculosis after the sensitivity of rpoB gene amplification by PCR is increased. In DNA sequencing, mutations in rpoB gene occur in RFP resistant strains of mycobacterial tuberculosis.