Thus, our study pointed out that mutation involved at codon 442Gln-His in RRDR
region is not conferring resistance in vivo and therefore, patients three and four in spite of showing this M.
tuberculosis based on genetic alteration in the RRDR
of rpoB and hatG gene are available within 3-5 days.
Amplification of RRDR of rpoB Gene Amplification of RRDR of rpoB gene of M.
Detection of Mutations in RRDR ofrpoBGene by Sequencing
The 365 bp region for V176F mutation and 749 bp region containing upstream region of RRDR were amplified and sequenced for mutation.
All three regions including the V176F codon, RRDR and upstream region of RRDR of rpoB gene in RIF resistant isolates were checked.
Using primers extending beyond the RRDR (the rpoB region surveyed by rapid molecular tests and responsible for >95% of RIF resistance mutations) the laboratory identified a novel rpoB gene mutation at codon 480 (ACC [right arrow] AAC; Thr [right arrow] Asn) and another previously described (3-5) mutation at codon 176 (GTC [right arrow] TTC; Val [right arrow] Phe) in the 2009 isolate, which has been implicated in RIF resistance.
The beginning of the rpoB gene in addition to the RRDR might be needed for identifying RIF/Rfb cross resistance in multidrug-resistant Mycobacterium tuberculosis isolates from southern China.
By exploring the use of staining dyes, entangled polymer sieving matrices, and detection schemes, we could identify point mutations in the RRDR of rpoB of Mtb that give rise to the rifampin-resistant phenotype.
3] Nonstandard abbreviations: HDA, heteroduplex analysis; CE, capillary electrophoresis; LPA, linear polyacrylamide; HEC, hydroxyethyl cellulose; UHG, universal heteroduplex generator; TB, tuberculosis; Mtb, Mycobacterium tuberculosis; RRDR, rifampin resistance-determining region; LSU, Louisiana State University; Rmp-r and Rmp-s, rifampin-resistant and -susceptible; UV, ultraviolet; LIF, laser-induced fluorescence; MC, methyl cellulose; TEMED, N,N,N',N'-tetramethylethylenediamine; [gamma]-MAPS, [gamma]-[(methoxyacryl)oxy]propyltrimethoxysilane; TAE, Tris-acetate-EDTA; and TBE, Tris-borate-EDTA.
No other mutations were identified in the DNA sequences outside the RRDR in these 3 isolates.
Mutations outside the RRDR account for <4% of rifampicin resistance, and few have been described (7-9).