Department of Medical Laboratory Sciences, Meru University of Science and Technology, Meru, Kenya.
National Tuberculosis Reference Laboratory, National Public Health Laboratories, Nairobi, Kenya.
Int J Mycobacteriol. 2024 Jul 1;13(3):258-264. doi: 10.4103/ijmy.ijmy_202_23. Epub 2024 Sep 14.
Drug-resistant tuberculosis (DR-TB) poses a major global challenge to public health and therapeutics. It is an emerging global concern associated with increased morbidity and mortality mostly seen in the low- and middle-income countries. Molecular techniques are highly sensitive and offer timely and accurate results for TB drug resistance testing, thereby positively influencing patient management plan.
The study was carried out at the National Tuberculosis Reference Laboratory (NTRL) in Kenya in the period between January and October 2022. A total of 243 Mycobacterium tuberculosis (M.tb) clinical isolates were included in the study. These isolates comprised of 50 isolates with mutations in rpoB, 51 isolates with katG mutations, 51 isolates with mutations in inhA, and 91 M.tb isolates lacking mutations in these genes based on Genotype MTBDRplus results. DNA from the isolates was extracted using the FluoroLyse extraction kit. Real-time polymerase chain reaction targeting the rpoB, InhA, and katG genes was performed using the FluoroType MTBDR amplification mix. Isolates with discordant results between Genotype MTBDRplus and FluoroCycler® MTBDR assays underwent targeted sequencing for the respective genes, then, sequences were analyzed for mutations using Geneious version 11.0 software.
The sensitivity of the Fluorocycler XT MTBDR assay for the detection of mutations that confer drug resistance was 86% (95% confidence interval [CI] 73.0-94.0) for rpoB, 96% (95% CI 87-100) for katG and 92% (95% CI 81-98) for inhA. The assay's specificity was 97% (95% CI 93-99) for rpoB, 98% (95% CI 96-100) for katG, and 97% (95% CI 93-99) for inhA.
The diagnostic accuracy of FluoroType MTBDR for the detection of mutations conferring resistance to rifampicin and isoniazid was high compared with that of Genotype MTBDRplus and demonstrates its suitability as a replacement assay for Genotype MTBDRplus.
耐药结核病（DR-TB）对公共卫生和治疗构成重大全球挑战。这是一个新出现的全球关注问题，与发病率和死亡率的增加有关，主要见于中低收入国家。分子技术具有高度敏感性，可为结核病药物耐药性检测提供及时、准确的结果，从而对患者管理计划产生积极影响。
本研究于 2022 年 1 月至 10 月在肯尼亚国家结核病参考实验室（NTRL）进行。共纳入 243 株结核分枝杆菌（M.tb）临床分离株。这些分离株包括 50 株 rpoB 基因突变株、51 株 katG 基因突变株、51 株 inhA 基因突变株和 91 株基于基因型 MTBDRplus 结果无这些基因突变的 M.tb 分离株。使用 FluoroLyse 提取试剂盒从分离株中提取 DNA。使用 FluoroType MTBDR 扩增混合物对 rpoB、InhA 和 katG 基因进行实时聚合酶链反应。对基因型 MTBDRplus 和 FluoroCycler® MTBDR 检测结果不一致的分离株进行相应基因的靶向测序，然后使用 Geneious 版本 11.0 软件对序列进行分析以确定突变。
Fluorocycler XT MTBDR 检测对耐药相关突变的检测灵敏度分别为 rpoB 86%（95%置信区间[CI]73.0-94.0）、katG 96%（95%CI87-100）和 inhA 92%（95%CI81-98）。该检测的特异性分别为 rpoB 97%（95%CI93-99）、katG 98%（95%CI96-100）和 inhA 97%（95%CI93-99）。
与基因型 MTBDRplus 相比，FluoroType MTBDR 检测对利福平及异烟肼耐药相关突变的诊断准确性较高，表明其适合替代基因型 MTBDRplus 检测。
