Makerere University, College of Health Sciences, Kampala, Uganda.
World Health Organisation Supranational Reference Laboratory, Uganda National TB Reference Laboratory, Kampala, Uganda.
BMC Infect Dis. 2022 Apr 11;22(1):363. doi: 10.1186/s12879-022-07339-w.
Second-line drug resistance (SLD) among tuberculosis (TB) patients is a serious emerging challenge towards global control of the disease. We characterized SLD-resistance conferring-mutations among TB patients with rifampicin and/or isoniazid (RIF and/or INH) drug-resistance tested at the Uganda National TB Reference Laboratory (NTRL) between June 2017 and December 2019.
This was a descriptive cross-sectional secondary data analysis of 20,508 M. tuberculosis isolates of new and previously treated patients' resistant to RIF and/or INH. DNA strips with valid results to characterise the SLD resistance using the commercial Line Probe Assay Genotype MTBDRsl Version 2.0 Assay (Hain Life Science, Nehren, Germany) were reviewed. Data were analysed with STATAv15 using cross-tabulation for frequency and proportions of known resistance-conferring mutations to injectable agents (IA) and fluoroquinolones (FQ).
Among the eligible participants, 12,993/20,508 (63.4%) were male and median (IQR) age 32 (24-43). A total of 576/20,508 (2.8%) of the M. tuberculosis isolates from participants had resistance to RIF and/or INH. These included; 102/576 (17.7%) single drug-resistant and 474/576 (82.3%) multidrug-resistant (MDR) strains. Only 102 patients had test results for FQ of whom 70/102 (68.6%) and 01/102 (0.98%) had resistance-conferring mutations in the gyrA locus and gyrB locus respectively. Among patients with FQ resistance, gyrAD94G 42.6% (30.0-55.9) and gyrA A90V 41.1% (28.6-54.3) mutations were most observed. Only one mutation, E540D was detected in the gyrB locus. A total of 26 patients had resistance-conferring mutations to IA in whom, 20/26 77.0% (56.4-91.0) had A1401G mutation in the rrs gene locus.
Our study reveals a high proportion of mutations known to confer high-level fluoroquinolone drug-resistance among patients with rifampicin and/or isoniazid drug resistance. Utilizing routinely generated laboratory data from existing molecular diagnostic methods may aid real-time surveillance of emerging tuberculosis drug-resistance in resource-limited settings.
耐二线药物结核病（TB）患者的二线药物耐药性是全球结核病控制面临的一个严重的新挑战。本研究旨在描述 2017 年 6 月至 2019 年 12 月期间在乌干达国家结核病参考实验室（NTRL）接受利福平（RIF）和/或异烟肼（INH）药物耐药性检测的新发病例和复治病例中耐 RIF 和/或 INH 的结核病患者的耐药性相关基因突变。
这是一项针对 20508 例新发病例和复治病例的 M. tuberculosis 分离株的描述性横断面二次数据分析，这些分离株对 RIF 和/或 INH 具有耐药性。使用商业线探针分析基因型 MTBDRsl 版本 2.0 检测试剂盒（Hain Life Science，Nehren，德国）对具有明确耐药性的 SLD 耐药性特征的 DNA 条进行了评估。采用 STATAv15 进行数据分析，采用交叉表法分析已知与注射用药物（IA）和氟喹诺酮类药物（FQ）耐药性相关的突变的频率和比例。
在符合条件的参与者中，12993/20508（63.4%）为男性，中位（IQR）年龄为 32（24-43）岁。共有 576/20508（2.8%）例 M. tuberculosis 分离株对 RIF 和/或 INH 具有耐药性。其中包括：102/576（17.7%）为单药耐药，474/576（82.3%）为多药耐药（MDR）菌株。只有 102 名患者接受了 FQ 检测，其中 70/102（68.6%）和 01/102（0.98%）在 gyrA 基因座和 gyrB 基因座分别具有耐药性相关的突变。在 FQ 耐药患者中，最常见的突变是 gyrAD94G（42.6%[30.0-55.9]）和 gyrA A90V（41.1%[28.6-54.3]）。在 gyrB 基因座仅检测到一个突变 E540D。共有 26 名患者对 IA 具有耐药性相关的突变，其中 20/26（77.0%[56.4-91.0]）在 rrs 基因座具有 A1401G 突变。
本研究揭示了在耐 RIF 和/或 INH 的患者中，与高水平氟喹诺酮类药物耐药性相关的突变比例较高。利用现有分子诊断方法常规生成的实验室数据，可能有助于实时监测资源有限环境中耐结核药物的新出现。
