Centre for Tuberculosis, National TB Reference Laboratory, National Institute for Communicable Diseases, a division of the National Health Laboratory Service, Johannesburg, South Africa.
Cepheid (PTY) LTD, Johannesburg, South Africa.
J Clin Microbiol. 2024 Aug 14;62(8):e0022924. doi: 10.1128/jcm.00229-24. Epub 2024 Jul 26.
Drug-resistant tuberculosis (TB) poses a significant public health concern in South Africa due to its complexity in diagnosis, treatment, and management. This study assessed the diagnostic performance of the Xpert MTB/XDR test for detecting drug resistance in patients with TB by using archived sputum sediments. This study analyzed 322 samples collected from patients diagnosed with TB between 2016 and 2019 across South Africa, previously characterized by phenotypic and genotypic methods. The Xpert MTB/XDR test was evaluated for its ability to detect resistance to isoniazid (INH), ethionamide (ETH), fluoroquinolones (FLQ), and second-line injectable drugs (SLIDs) compared with phenotypic drug susceptibility testing (pDST) and whole-genome sequencing (WGS). Culture, Xpert MTB/RIF Ultra, and Xpert MTB/RIF (G4) tests were performed to determine sensitivity and agreement with this test for TB detection. The sensitivities using a composite reference standard, pDST, and sequencing were >90% for INH, FLQ, amikacin (AMK), kanamycin (KAN), and capreomycin (CAP) resistance, meeting the WHO target product profile criteria for this class. A lower sensitivity of 65.9% (95% CI: 57.1-73.6) for ETH resistance was observed. The Xpert MTB/XDR showed a sensitivity of 98.3% (95% CI: 96.1-99.3) and specificity of 100% (95% CI: 86.7-100) compared with culture, a positive percent agreement (PPA) of 98.8% (95% CI: 93.7-99.8) and negative percent agreement (NPA) of 100.0% (95% CI: 78.5-100.0) compared with G4, and a PPA of 99.5% (95% CI: 97.3-99.9) and NPA of 100.0% (95% CI: 78.5-100.0) compared with Xpert MTB/RIF Ultra for detecting . The test offers a promising solution for the rapid detection of drug-resistant TB and could significantly enhance control efforts in this setting.
耐多药结核病（TB）在南非由于其诊断、治疗和管理的复杂性而构成重大公共卫生关切。本研究评估了 Xpert MTB/XDR 测试在使用存档痰液沉淀物检测 TB 患者耐药性方面的诊断性能。本研究分析了 2016 年至 2019 年期间在南非收集的 322 例经诊断患有结核病的患者样本，这些样本先前通过表型和基因型方法进行了特征描述。与表型药物敏感性测试（pDST）和全基因组测序（WGS）相比，评估了 Xpert MTB/XDR 测试检测异烟肼（INH）、乙胺丁醇（ETH）、氟喹诺酮类（FLQ）和二线注射药物（SLIDs）耐药性的能力。进行了培养、Xpert MTB/RIF Ultra 和 Xpert MTB/RIF（G4）测试，以确定对 TB 检测的敏感性和与该测试的一致性。使用复合参考标准、pDST 和测序的 INH、FLQ、阿米卡星（AMK）、卡那霉素（KAN）和卷曲霉素（CAP）耐药性的敏感性>90%，符合该类别世界卫生组织目标产品概况标准。ETH 耐药性观察到的敏感性较低，为 65.9%（95%CI：57.1-73.6）。与培养相比，Xpert MTB/XDR 显示出 98.3%（95%CI：96.1-99.3）的敏感性和 100%（95%CI：86.7-100）的特异性，与 G4 的阳性百分比吻合率（PPA）为 98.8%（95%CI：93.7-99.8）和阴性百分比吻合率（NPA）为 100.0%（95%CI：78.5-100.0），与 Xpert MTB/RIF Ultra 的 PPA 为 99.5%（95%CI：97.3-99.9）和 NPA 为 100.0%（95%CI：78.5-100.0）相比，用于检测. 该测试为快速检测耐多药结核病提供了一个有前途的解决方案，可显著加强该环境中的控制工作。
