Study of rpoB Mutation in Rifampin Resistants Mycobacterium Tuberculosis

Objective To understand the rpoB gene mutation in M.tuberculosis isolates,and to evaluate their clinical value.Method 335 clinical isolates of mycobacterium tuberculosis(109 isolates drug susceptible,246 isolates rifampin-resistance or multidrug resistance including rifampin) were detected using polymerase chain reaction-single strand conformation polymorphism(PCR-SSCP).Results SSCP pattern of reference mycobacterium tuberculosis H37Rv as control,no mutation was found in rifampin-suscepitible 109 strains.SSCP patterns of 225/246 rifampin resistant clinical isolates were different from the normal control.The sensitivity was 91 5%.31 resistant isolates,included 25 abnormal isolates and 6 normal isolates of SCCP were identified.Sequencing showed 29 isolates had rpoB gene mutations and 3 isolates were not found rpoB gene mutations.The 3 most frequent rpoB gene mutation situs were Leu-531(19 isolates.TCGTTG) and His-526(7 isolates,CACTAC) and Asp-516(3 isolates,GACGTC).Conclusions The results confirm that rpoB gene mutation is the most important mechanism in rifampin resistant tuberculosis mutation situs are 531 tryptophan and 526 histidine;respectively.It is feasible that using PCR-SSCP to detect drug resistance in mycobacterium tuberculosis.