Mchaki Betty R, Mgaya Fauster X, Kunambi Peter P, Hang'ombe Bernard, Matee Mecky I, Munyeme Musso
Department of Disease Control, School of Veterinary Medicine, University of Zambia, P.O. Box 32379, Lusaka 10101, Zambia.
Department of Microbiology and Immunology, Muhimbili University of Health and Allied Sciences, P.O. Box 65001, Dar es Salaam 11103, Tanzania.
Antibiotics (Basel). 2022 Oct 27;11(11):1489. doi: 10.3390/antibiotics11111489.
Rapid, accurate and reliable assays are required for timely detection of drug-resistant tuberculosis and early initiation of second-line TB treatment as well as to minimize transmission of resistant strains. This study assessed diagnostic performance characteristics of two rapid molecular assays, line probe assay (LPA) and GeneXpert (MTB/RIF), in the detection rifampicin monoresistance using the phenotypic proportion method on Lowenstein−Jensen media as the gold standard. This study involved a total of 357 isolates, 74 rifampicin-resistant and 283 rifampicin-susceptible, collected at the Central Tuberculosis Reference Laboratory (CTRL) in Dar es Salaam, Tanzania, between 2016 and 2019. Sensitivity, specificity and positive and negative predictive values were used to assess the performance characteristics of the two assays while kappa coefficient was used to determine agreement of test results. The receiver operating curve (ROC) was used to determine the discriminatory ability of the test in distinguishing resistant and susceptible TB isolates. Our results showed that GeneXpert had sensitivity, specificity and positive and negative predictive values of 93.2, 82.7, 58.5 and 97.9%, respectively; the corresponding performance for LPA was 86.5, 97.5, 90.1 and 96.5%, respectively. Compared with conventional phenotypic DST results, GeneXpert had a moderate agreement (kappa 0.621, p < 0.001), while LPA had high agreement (0.853, p < 0.001). LPA showed an accuracy of 95.2% compared to GeneXpert’s 84.9%. ROC curve depicted the ability of the tests to distinguish rifampicin-sensitive and rifampicin-resistant strains to be 87.9% for GeneXpert and 92.0% for LPA. Our results indicate the superiority of LPA over GeneXpert regarding detection of rifampicin monoresistance. However, logistic challenges such as longer turnaround time and need for skilled laboratory personnel may limit its use.
为了及时检测耐多药结核病并尽早开始二线结核病治疗，以及尽量减少耐药菌株的传播，需要快速、准确和可靠的检测方法。本研究以罗氏培养基上的表型比例法作为金标准，评估了两种快速分子检测方法——线性探针检测法（LPA）和GeneXpert（MTB/RIF）在检测利福平单耐药方面的诊断性能特征。本研究共纳入了2016年至2019年间在坦桑尼亚达累斯萨拉姆中央结核病参考实验室（CTRL）收集的357株菌株，其中74株对利福平耐药，283株对利福平敏感。使用灵敏度、特异性、阳性和阴性预测值来评估这两种检测方法的性能特征，同时使用kappa系数来确定检测结果的一致性。采用受试者工作特征曲线（ROC）来确定检测方法区分耐药和敏感结核菌株的鉴别能力。我们的结果显示，GeneXpert的灵敏度、特异性、阳性和阴性预测值分别为93.2%、82.7%、58.5%和97.9%；LPA的相应性能分别为'86.5%、97.5%、90.1%和96.5%。与传统的表型药物敏感性试验结果相比，GeneXpert的一致性中等（kappa 0.621，p < 0.001），而LPA的一致性较高（0.853，p < 0.001）。与GeneXpert的84.9%相比，LPA显示出95.2%的准确率。ROC曲线显示，GeneXpert区分利福平敏感和利福平耐药菌株的能力为87.9%，LPA为92.0%。我们的结果表明，在检测利福平单耐药方面，LPA优于GeneXpert。然而，诸如周转时间较长和需要熟练的实验室人员等后勤挑战可能会限制其使用。
