Abstract: Objective Genetic evaluation of relationship between rpoB gene mutation and rifampin-resistance in Mycobacterium Tuberculosis（MTB）. Methods This study was carried out on 81 clinical isolates with drug susceptibility testing and genotypic analysis by PCR amplification and sequencing of rpoB gene. Results Among these isolates, there were 27 rifampin-resistant and 54 susceptible strains. Of the 27 drug-resistant isolates, 20 (74.1%) carried mutations on the amplified fragment of the rpoB gene with 10 mutation types at seven codons including 531 and 526, and two new mutation patterns were recognized. On the other hand, one mutation (1.9%) appeared in 54 drug- susceptible strains. Conclusion The study showed geographical variation in the mutation types of rpoB gene in M. tuberculosis isolates from Guizhou of China, and this finding is valuable for the development of rapid molecular diagnostic methods suitable for specific regions.

Key words: Mycobacterium tuberculosis, Rifampin, rpoB, Mutation, Drug susceptibility