Department of Clinical Microbiology, 12 de Octubre University Hospital, Madrid, Spain.
Department of Clinical Microbiology, 12 de Octubre University Hospital, Madrid, Spain.
Diagn Microbiol Infect Dis. 2021 Feb;99(2):115235. doi: 10.1016/j.diagmicrobio.2020.115235. Epub 2020 Oct 7.
The Xpert MTB/RIF assay is a molecular assay that has improved the detection of tuberculosis and rifampicin resistance. However, its sensitivity is limited in patients with paucibacillary disease. Xpert MTB/RIF Ultra has been developed to resolve this limitation. We compared the performance of Xpert Ultra with that of culture for detection of Mycobacterium tuberculosis and rifampicin resistance. We reviewed laboratory records for 848 respiratory and 419 extrarespiratory samples that were processed between April 2018 and October 2019. The sensitivity, specificity, negative predictive value, and positive predictive value of Xpert Ultra were 94.8%, 98%, 98.8%, and 91.3% for respiratory samples and 83.8%, 96.9%, 98.4% and 72.1% for nonrespiratory ones. We found 26 culture-negative/Ultra-positive samples. Most of them have low bacillary burden and more than half belonged to patients with history of tuberculosis. Xpert Ultra demonstrates excellent diagnostic accuracy for tuberculosis detection, including paucibacillary specimens. In patients with history of tuberculosis, PCR results should be interpreted carefully.
Xpert MTB/RIF assay 是一种分子检测方法，可提高结核病和利福平耐药性的检测率。然而，其在菌载量低的患者中的敏感性有限。为了解决这一局限性，开发了 Xpert MTB/RIF Ultra。我们比较了 Xpert Ultra 与培养法检测结核分枝杆菌和利福平耐药性的性能。我们回顾了 2018 年 4 月至 2019 年 10 月期间处理的 848 份呼吸道和 419 份非呼吸道样本的实验室记录。Xpert Ultra 对呼吸道样本的敏感性、特异性、阴性预测值和阳性预测值分别为 94.8%、98%、98.8%和 91.3%，对非呼吸道样本的敏感性、特异性、阴性预测值和阳性预测值分别为 83.8%、96.9%、98.4%和 72.1%。我们发现了 26 份培养阴性/Ultra 阳性的样本。它们中的大多数菌载量较低，超过一半的患者有结核病病史。Xpert Ultra 对结核病检测具有出色的诊断准确性，包括菌载量低的标本。对于有结核病病史的患者，PCR 结果应仔细解读。
