Dept of Microbiology, AGMC, Tripura, India.
Dept of Microbiology, TRIHMS, Arunachal Pradesh, India.
Indian J Med Microbiol. 2023 Sep-Oct;45:100399. doi: 10.1016/j.ijmmb.2023.100399. Epub 2023 Jun 28.
Rifampicin (RIF), one of the first line drug in treatment of tuberculosis. It acts on rpoB gene which encodes RNA polymerase β subunit. In 95% of RIF resistant cases, mutations are present in rpoB gene. Most of them are within 81bp RIF-resistance determining region (RRDR).Xpert MTB/RIF assay has been tremendously revolutionalised the diagnosis of tuberculosis (TB).Also sequencially detect bacteria and resistance to rifampicin (rif).Approximately 96% of rif-resistant Mycobacterium tuberculosis (MTB) strains worldwide, showed mutations in a region at the 507-533rd amino acid residuals (81 bp) in the MTB rpoB gene. Here evaluation is made about frequent regions of amplification and mutation in various codons of 81bp of rpoB gene in rif sensitive and rif resistant cases.
A total of 4116 samples were received at Mycobacteriology laboratory, AGMC and processed in CBNAAT.Data of MTB detected samples were collected & statistically analysed to detect frequency of amplification & no amplification in various regions of 81bp of rpoB genes.
Out of 4116 samples, MTB was detected in 1323 samples. Among them 1291 (97.58%) cases were Rif sensitive (RS) and 32 (2.41%) cases were rif resistance (RR).Most of the MTBC detected samples showed amplification in probe A then in probe C.78.12% rif resistant cases showed mutation in either of the probe, commonest is probe E. Study also showed low bacillary loads in most of the RR cases.
Study highlighted variations in amplification of different regions of 81bp of rpoB gene in MTBC detected cases. North-east India, like other part of world, also showed highest frequency of mutation in probe E in rif resistant cases.
利福平（RIF）是治疗结核病的一线药物之一。它作用于 rpoB 基因，该基因编码 RNA 聚合酶β亚基。在 95%的 RIF 耐药病例中，rpoB 基因存在突变。它们中的大多数位于 81bp 的 RIF 耐药决定区（RRDR）内。Xpert MTB/RIF 检测极大地革新了结核病（TB）的诊断。它还可以连续检测细菌和对利福平（rif）的耐药性。全世界约 96%的耐 rif 结核分枝杆菌（MTB）菌株在 MTB rpoB 基因的第 507-533 位氨基酸残基（81bp）的一个区域显示出突变。在这里，评估了 rif 敏感和 rif 耐药病例中 rpoB 基因 81bp 不同密码子中扩增和突变的常见区域。
共收到 4116 份标本至 AGMC 的分枝杆菌实验室，并在 CBNAAT 中进行处理。收集并统计分析 MTB 检测样本的数据，以检测 rpoB 基因 81bp 不同区域的扩增和无扩增频率。
在 4116 份样本中，在 1323 份样本中检测到 MTB。其中 1291 例（97.58%）为 rif 敏感（RS），32 例（2.41%）为 rif 耐药（RR）。大多数检测到的 MTBC 样本显示探针 A 然后是探针 C 的扩增。78.12%的 rif 耐药病例在任一探针中均显示突变，最常见的是探针 E。研究还表明，大多数 RR 病例的细菌负荷较低。
该研究强调了在检测到的 MTBC 中 rpoB 基因不同区域的扩增存在差异。东北印度与世界其他地区一样，在 rif 耐药病例中也显示出探针 E 突变的最高频率。
