Department of Epidemiology and Statistics, North China University of Science and Technology, Tangshan 063210, Hebei, China.
Department of Laboratory Medicine, The Fifth Affiliated Hospital of Shijiazhuang, North China University of Science and Technology, Shijiazhuang 050021, Hebei, China.
J Glob Antimicrob Resist. 2019 Sep;18:168-176. doi: 10.1016/j.jgar.2019.03.012. Epub 2019 Mar 27.
Multidrug-resistant tuberculosis (MDR-TB) is a major public-health problem in China. However, there is little information on the molecular characterisation of clinical MDR-TB isolates in Hebei Province.
In this study, 123 MDR-TB isolates were identified in sputum cultures using traditional drug susceptibility testing. The isolates were analysed for mutations in seven genes associated with resistance to antituberculous four drugs: katG and inhA promoter for isoniazid (INH); rpoB for rifampicin (RIF); gyrA and gyrB for ofloxacin (OFLX); and rrs and eis promoter for kanamycin (KAN). All strains were genotyped by spoligotyping and 15-loci MIRU-VNTR analysis.
A total of 39 distinct mutations were found at the seven loci in 114/123 (92.7%) MDR-TB isolates. Frequencies of INH, RIF, OFLX and KAN resistance-associated mutations were 82.1% (101/123), 83.7% (103/123), 92.1% (35/38) and 76.2% (16/21), respectively. The most prevalent mutations involved in resistance were: Ser315Thr in katG (70/123; 56.9%) and C(-15)T in inhA (15/123; 12.2%) for INH; Ser531Leu in rpoB (72/123; 58.5%) for RIF; Asp94Gly in gyrA (10/38; 26.3%) for OFLX; and A1401G in rrs (12/21; 57.1%) for KAN. Four novel gyrB mutants (Leu442Leu, Ser447Phe, Asn499Thr and Ala504Val) were identified. Mutations in katG, rpoB (or both) and the inhA promoter showed a sensitivity of 75.6% and specificity of 97.0% for detection of MDR-TB. DNA sequencing of the seven loci was 57.1% sensitive and 91.0% specific for prediction of XDR-TB isolates.
These results may be of value in rapid molecular detection of MDR- and XDR-TB isolates in clinical samples in Hebei Province.
耐多药结核病（MDR-TB）是中国的一个主要公共卫生问题。然而，有关河北省临床 MDR-TB 分离株的分子特征的信息很少。
本研究采用传统药物敏感性试验，从痰培养物中鉴定了 123 例 MDR-TB 分离株。对与抗结核四种药物耐药相关的七个基因中的突变进行了分析：异烟肼（INH）的 katG 和 inhA 启动子；利福平（RIF）的 rpoB；氧氟沙星（OFLX）的 gyrA 和 gyrB；卡那霉素（KAN）的 rrs 和 eis 启动子。所有菌株均通过 spoligotyping 和 15 个位点 MIRU-VNTR 分析进行基因分型。
在 123 例 MDR-TB 分离株的七个基因座中发现了 39 个不同的突变，其中 114 例（92.7%）存在突变。INH、RIF、OFLX 和 KAN 耐药相关突变的频率分别为 82.1%（101/123）、83.7%（103/123）、92.1%（35/38）和 76.2%（16/21）。最常见的耐药相关突变涉及：katG 中的 Ser315Thr（70/123；56.9%）和 inhA 中的 C(-15)T（15/123；12.2%）用于 INH；rpoB 中的 Ser531Leu（72/123；58.5%）用于 RIF；gyrA 中的 Asp94Gly（10/38；26.3%）用于 OFLX；rrs 中的 A1401G（12/21；57.1%）用于 KAN。鉴定了四个新的 gyrB 突变体（Leu442Leu、Ser447Phe、Asn499Thr 和 Ala504Val）。katG、rpoB（或两者）和 inhA 启动子的突变对检测 MDR-TB 的敏感性为 75.6%，特异性为 97.0%。七个基因座的 DNA 测序对预测 XDR-TB 分离株的敏感性为 57.1%，特异性为 91.0%。
这些结果可能对河北省临床样本中 MDR-TB 和 XDR-TB 分离株的快速分子检测有价值。
