Study on Mutation of Rifampin-resistant Genes Mycobacterium tuberculosis

Objective To detect rpoB gene mutations in refampin-resistant Mycobacterium tuberculosis using Polymerase Chain reaction-single-strand conformation polymorphism(PCR-SSCP)and DNA sequencing. Method 91 clinical isolates of Mycobacterium tuberculosis(35 drug susceptible,56 RFP-resistance or multiple drug resistance including rifampin)by DNA sequencing and PCR-SSCP. Results No mutation was found in 35 rif-sensitive strains by DNA sequencing.While 53 of 56 rifampinsensitive strains had mutations rifampin-resistant determination region of rpoB gene,the mutation rate was 94.6(53/56),531-Ser and 526-His were the most common positions to be substituted.35 rif-sensitive strains had same PCR-SSCP gelprofile with Mycobacterium tuberculosis H_ 37 Rv as control,while 52 of 56 rif-sensitive strains showed different SSCP.The specificity is 92.9. Conclusion DNA sequencing is valuable in rifampin susceptibilty test,PCR-SSCP is useful in rifampin resistance strains screening.