Rapid Detection of Mutation in RRDR of rpo B Gene for Rifampicin Resistance in MDR-Pulmonary Tuberculosis by DNA Sequencing

Abstract

To detect the site of mutation in RRDR of rpo B gene for rifampicin resistance in MDR-TB by DNA sequencing. 50 MDR-TB patients were enrolled in our study after informed written consent. Mycobacterial DNA was extracted from sputum samples by Universal Sample Processing (USP) method and RRDR of rpo B gene was amplified by PCR using primers RP4T and RP8T and then sequenced by automated DNA sequencing. The nucleotide sequences of RRDR of rpo B gene were compared with the reference sequence. We observed three different types of mutation in the RRDR of rpo B gene. The frequency of mutation in codon 531 (TCG ? TTG), 526 (CAC ? TAC) and 516 (GAC ? GTC) are 60, 26.6 and 6.6% respectively. Of the total cases studied, 6.6% cases, although resistant to rifampicin, did not show any mutation in the RRDR of rpo B gene. Codon 531 (TCG ? TTG) is the most common site of mutation in RRDR of rpo B gene for rifampicin resistance in MDR-pulmonary tuberculosis followed by codon 526 (CAC ? TAC) and codon 516 (GAC ? GTC).

Characterization of katG, inhA, rpoB and pncA in Mycobacterium tuberculosis isolates from MDR-TB risk patients in Thailand

“…Here, the most common mutation involved in RIF resistance was a missense mutation in codon Ser531Leu of rpoB (Table 3). These results were similar to those of previous studies [26,32,33]. The frequency of this mutation in this study was 79% (41/52) whereas other studies reported frequencies of 27% [24], 64% [29] and 60% [30].…”

Rapid Genotypic Detection of rpoB and katG Gene Mutations in Mycobacterium tuberculosis Clinical Isolates from Northern India as Determined by MAS‐PCR

“…In the present study, among RIF‐resistant isolates, 59.83% had mutation in codon 531 of rpoB gene, which was similar to other studies; 58% , 60% , and 59% . However, a higher proportion, i.e., 70.5% was reported by Barnard et al .…”

“…The frequency of mutation at codon 526 was observed among 45.29% of RIF‐resistant isolates, which was found to be much higher than that of the studies from four east Asian countries , Latvia , and India , which ranged between 10% and 27%. The rate of mutation at 516 was higher (22.22%) than the range reported elsewhere . However, our observation is in accordance with reports from East Asia and Latvia , where higher mutational frequencies in codon 516 (15–32%) along with a predominant Beijing genotype were reported.…”

“…However, a higher proportion, i.e., 70.5% was reported by Barnard et al (22). The frequency of mutation at codon 526 was observed among 45.29% of RIFresistant isolates, which was found to be much higher than that of the studies from four east Asian countries (23), Latvia (24), and India (20), which ranged between 10% and 27%. The rate of mutation at 516 was higher (22.22%) than the range reported elsewhere (20,22,25).…”

Emerging Trend of Mutation Profile of rpoB Gene in MDR Tuberculosis, North India

“…Rest two samples did not show any mutation RRDR region. Study on 50 samples of MDR patients from North India found mutation at codon 531 (60 %), 526 (26.6 %) and 516 (6.6 %) and no mutation (6.6 %) in RRDR region of rpoB gene [22].…”