Characterization and Rapid Detection of Mutations in RpoB Gene of Rifampin Resistant Mycobacterium Tuberculosis Strains

Purpose To elucidate the characterization of rpoB mutations in rifampin resistant clinical mycobacterium tuberculosis isolates from Shanghai,and explore the significance of DNA sequencing of rpoB gene in the diagnosis of M. tuberculosis resistance to rifampin. Methods 58 isolates of M. tuberculosis including 36 rifampin resistant strains and 22 susceptible strains were studied.A fragment(213 bp)of rpoB gene of all of the 58 isolates was amplified and sequenced,which comprise the 69 bp rifampin resistance determination region. Results All of the 36 rifampin resistant isolates had mutation in the 69 bp region of rpoB gene,and there were no mutations in any of the susceptible strains.The mutation of 531 Ser and 526 His contributed to 47.2% and 25.0% res pectively of all the mutations. Conclusions Mutations in the 69 bp hypervariable region of rpoB are the main reason of M. tuberculosis resistant to rifampin.531 Ser and 526 His are the most common positions of mutations.