Study on rpoB genes of rifampin-resistant Mycobacterium tuberculosis

Objective To investigate the mutations of rpoB genes interrelated rifampin(RFP) resistance of Mycobacterium tuberculosis(Mt) in Hangzhou area. Methods 90 strains of Mt from the patients were chosen randomly. rpoB genes were performed by PCR amplification and direct sequencing, and contrasted the rpoB DNA sequences of the strains with the rpoB sequences of Mt wild-type strain (RFP sensitive). Results The results indicated that there were 39 strains of RFP-resistant Mt and 51 strains of RFP-sensitive Mt. Furthermore, the results from PCR and sequencing were the same to the results from drug susceptibility testing. The rate of RFP-resistant Mt was 43%. The substitution at single codon in 526(63.6%) or 531(36.4 %) was found in all 11 strains of RFP-resistant. 11 sensitive strains of RFP were not detected the mutation in 531 or 526 points. Conclusions The results reveal that there is a strong correlation between resistance to rifampin and rpoB mutations of M. tuberculosis, but the report about the substitution at single codon mutation in 526(63.6%) have not found in published reports. the sequencing analysis of the rpoB fragment amplified by PCR may accurately identify the rifampin-resistant or multiple resistant strains of M. tuberculosis.