Background: Mutations in the rpoB gene, which encodes the β-RNA-polymerase subunit, occur in an 81-bp area called the Rifampicin Resistant Determining Region (RRDR) in codons 507 to 533. This point mutation area is used to rapidly identify rifampicin-resistant isolates. Mutations in the rpoB gene area in MTb, in addition to having changes in phenotypic properties that cause resistance to the m…