Mutation in the RRDR region of rpoB is detected using 8 wild type immobilized probes along with 4 other probes that detect most common substitution at codon 516, 526 and 531 as in Figure-1.7 Each probe binds to its corresponding complementary codon.
TB-SPRINT is commercial assay used for determining DNA polymorphism at the DR locus and simultaneously detects mutation in RRDR region of rpoB gene.10
For the detection of mutations at codon within
RRDR of rpoB for rifampicin, real-time PCR-HRM analysis was performed.
Rifampicin resistance as reported in previous studies is due to mutation in the Rifampicin Resistance Determining Region (
RRDR) of rpoB gene.
About 200 ngof DNA from culture isolates while 5 L of DNA from clinical specimens was used as target for the amplificationof hotspot region of rpoB gene by polymerase chainreactions.Amplification of
RRDR of rpoB Gene Amplification of
RRDR of rpoB gene of M.
The 365 bp region for V176F mutation and 749 bp region containing upstream region of
RRDR were amplified and sequenced for mutation.
Silent mutations within the
RRDR of the rpoB gene have been reported,21 though codon 526 mutations are very strongly associated with RIF resistance.
Shortly thereafter, a line probe assay (GenoType MTBDRplus; HAIN Lifescience, Nehren, Germany) performed by Southeastern National TB Center (Gainesville, FL, USA) on the culture of the sputum specimen obtained at admission indicated an inhA point mutation but no mutation in the
RRDR region of the rpoB gene, which suggested that the isolate was INH resistant but RIF susceptible.
The samples consisted of pooled PCR products containing a 193-bp fragment from the
RRDR of the rpoB gene of Mtb that were amplified from different Rmp-r strains of Mtb (minimum inhibitory concentration >2 mg/L rifampin).
RRDR (1999) INSCAN -- International Settlement Canada Research Resource Division for Refugees Volume 12 (4), Carleton University
RRDR, Ottawa, Canada.
Amplification of
RRDR of rpoB gene yielded 270 bp products compared to DNA size marker in agarose gel electrophoresis (Fig.
This region is known as the rifampicin resistance-determining region (
RRDR), or "hotspot," and is used as a target for direct sequencing and commercial line probe assays.