Mutations in theRRDR of the rpoB gene of rifampin-resistant Mycobacterium tuberculosis clinical isolates from Sichuan in China

Sequencing of the rpoB gene was performed for 268 randomly selected isolates,including 213 rifampin-resistant and 55 rifampin-susceptible isolates.Mutations in the RRDR of rpoB gene were detected in 200(93.90%) of 213 rifampin-resistant isolates and none of the 55 rifampin-susceptible isolates.The most common mutations were in codon 531(55.87%),526(16.43%),516(10.33%) and 511(8.92%),together accounting for 91.55% of rifampin-resistant isolates.It is demonstrated that mutation frequency of codon 511 in Sichuan was higher than in other provinces of China.