Sultana Monika, Alam Mohammad Mamun, Mistri Somen Kumar, Mostafa Kamal S M, Ahsan Chowdhury Rafiqul, Yasmin Mahmuda
Department of Microbiology, University of Dhaka, Dhaka-1000, Bangladesh.
National Tuberculosis Reference Laboratory (NTRL), Dhaka-1207, Bangladesh.
Iran J Microbiol. 2024 Aug;16(4):459-469. doi: 10.18502/ijm.v16i4.16304.
Rifampicin (RIF) and isoniazid (INH), two most potent antibiotics, are prescribed to cure tuberculosis. , the causative agent of multidrug-resistant tuberculosis (MDR-TB), is resistant to these first-line drugs. Here, two molecular techniques were demonstrated such as PCR sequencing-based and GeneXpert assay for rapidly identifying MDR-TB.
Pulmonary samples (sputum) were collected from 55 MDR-TB suspected patients from the National Tuberculosis Reference Laboratory (NTRL), Dhaka where the research work was partially accomplished and continued in the department of Microbiology, University of Dhaka, Bangladesh. We strived for sequencing technique as well as GeneXpert assay to identify mutations in B and G genes in MTB strains and sputum directly. Culture-based drug susceptibility testing (DST) was performed to measure the efficacy of the molecular methods employed.
When analyzed, B gene mutations at codons 531 (54.54%), 526 (14.54%), and 516 (10.91%) were found by sequencing in 80% of the samples. Nucleotide substitution at G315 (AGC→ACC) was spotted in 16 (76.19%) out of 21 samples. When comparing the sequencing results with DST, sensitivity and specificity were investigated to determine drug-resistance (rifampicin-resistance were 98 and 100% whereas isoniazid-resistance were 94 and 100% respectively). Additionally, as a point of comparison with DST, only 85.45% of RIF mono-resistant TB cases were accurately evaluated by the GeneXpert assay.
This research supports the adoption of PCR sequencing approach as an efficient tool in detecting MDR-TB, counting the higher sensitivity and specificity as well as the short period to produce the results.
利福平（RIF）和异烟肼（INH）是两种最有效的抗生素，用于治疗结核病。耐多药结核病（MDR-TB）的病原体对这些一线药物具有耐药性。在此，展示了两种分子技术，如基于PCR测序的技术和GeneXpert检测法，用于快速鉴定耐多药结核病。
从达卡国家结核病参考实验室（NTRL）的55例疑似耐多药结核病患者中采集肺部样本（痰液），研究工作在该实验室部分完成，并在孟加拉国达卡大学微生物学系继续进行。我们致力于采用测序技术以及GeneXpert检测法直接鉴定结核分枝杆菌菌株和痰液中B和G基因的突变。进行基于培养的药物敏感性试验（DST）以评估所采用分子方法的有效性。
分析时，通过测序在80%的样本中发现密码子531（54.54%）、526（14.54%）和516（10.91%）处的B基因突变。在21个样本中的16个（76.19%）中发现G315处的核苷酸替换（AGC→ACC）。将测序结果与DST进行比较时，研究了敏感性和特异性以确定耐药性（利福平耐药性分别为98%和100%，而异烟肼耐药性分别为94%和100%）。此外，作为与DST的比较点，GeneXpert检测法仅准确评估了85.45%的利福平单耐药结核病病例。
本研究支持采用PCR测序方法作为检测耐多药结核病的有效工具，因其具有较高的敏感性和特异性以及较短的结果产出时间。
