Communicable Disease Control (CDC), Directorate General of Health Services, Mohakhali, Dhaka 1212, Bangladesh.
Department of Microbiology & Immunology, Bangabandhu Sheikh Mujib Medical University, Shahbag, Dhaka, Bangladesh.
Infect Genet Evol. 2020 Dec;86:104634. doi: 10.1016/j.meegid.2020.104634. Epub 2020 Nov 11.
Bangladesh is among the high burden countries for tuberculosis (TB) and multidrug resistant TB (MDR-TB). As the genetic diversity and distinct phylogeographic distribution of Mycobacterium tuberculosis are responsible for regional differences in drug resistance, this cross sectional study was conducted to identify the circulating M. tuberculosis strains belonging to different lineages among pulmonary tuberculosis and, to investigate the contribution of distinct M. tuberculosis lineages to rifampicin resistant (RR) and rifampicin sensitive (RS) TB. A total of 40 RR and 20 RS isolates were enrolled in this study, all of which confirmed as M. tuberculosis by MPT 64 antigen detection. Furthermore, all isolates were genotyped by 24 loci Mycobacterial Interspersed Repetitive Units-Variable Number of Tandem Repeats (MIRU-VNTR), thus comprising the first study to employ this approach in Bangladesh. Beijing was the predominant lineage (26.8%) followed by EAI (23.2%), Delhi/CAS (16.1%), H37Rv (8.9%), Haarlem (7.1%), LAM (5.4%), Cameroon (3.6%) and a NEW-1 (1.8%). Four (7.1%) isolates remained as unidentified. Beijing strains were the significantly predominant (36.8%; p = 0.0135) among the RR isolates in comparison with other strains whereas EAI was the predominant (38.8%) lineage among RS isolates. Also, approximately 13% RR isolates showed genotypic resistance against fluoroquinolones by LPA and, hence, classed as pre-XDR TB albeit no specific lineage was found associated with these latter strains. A low transmission rate (10.5%) and high genetic diversity was detected in this setting with all the clustered strains herein identified belonging to the Beijing lineage. This study highlights 24 loci MIRU-VNTR analysis as a powerful tool for genotyping of Mycobacterium tuberculosis in this setting as it shows a high discriminatory index (0.81).
孟加拉国是结核病（TB）和耐多药结核病（MDR-TB）负担较高的国家之一。由于结核分枝杆菌的遗传多样性和独特的系统地理学分布是导致耐药性区域差异的原因，因此进行了这项横断面研究，以确定在肺结核患者中属于不同谱系的循环结核分枝杆菌菌株，并调查不同结核分枝杆菌谱系对利福平耐药（RR）和利福平敏感（RS）TB 的贡献。本研究共纳入 40 株 RR 和 20 株 RS 分离株，所有分离株均通过 MPT64 抗原检测确认为结核分枝杆菌。此外，所有分离株均通过 24 个基因座分枝杆菌插入重复可变数量串联重复（MIRU-VNTR）进行基因分型，这是在孟加拉国首次采用这种方法的研究。北京株是主要谱系（26.8%），其次是 EAI（23.2%）、Delhi/CAS（16.1%）、H37Rv（8.9%）、Haarlem（7.1%）、LAM（5.4%）、Cameroon（3.6%）和 NEW-1（1.8%）。有 4 株（7.1%）分离株仍无法识别。RR 分离株中，北京株明显占优势（36.8%；p=0.0135），而 EAI 是 RS 分离株中主要的谱系（38.8%）。此外，约 13%的 RR 分离株通过 LPA 显示对氟喹诺酮类药物的基因型耐药性，因此被归类为预广泛耐药结核病，尽管没有发现与这些菌株相关的特定谱系。在这种情况下，检测到低传播率（10.5%）和高遗传多样性，所有聚类菌株均属于北京谱系。本研究强调了 24 个基因座 MIRU-VNTR 分析作为该环境中结核分枝杆菌基因分型的有力工具，因为它显示出较高的区分指数（0.81）。
