A quantitative adaptation of the Wayne test for pyrazinamide resistance
A quantitative adaptation of the Wayne test for pyrazinamide resistance
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DOI：
10.1016/j.tube.2016.03.011
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发表时间：
2016-07-01
期刊：
影响因子：
3.2
通讯作者：
Sheen, Patricia
中科院分区：
文献类型：
--
作者：
Meinzen, Christopher;Proano, Alvaro;Sheen, Patricia
背景资料：吡嗪酰胺（PZA）是治疗潜伏期结核病（TB）的最重要药物，用于一线和二线治疗方案。持续增加的多药耐药结核病和PZA耐药的患病率，使替代检测的发展，及时鉴定PZA耐药的所有更important.Methods：我们标准化和评估的定量变化的韦恩测定（QW）确定PZA耐药结核分枝杆菌菌株。该测定定量M。用可见分光光度法测定结核菌代谢PZA和产生吡嗪酸（POA）的能力。我们使用浓度为400 μ g/ml和800 μ g/ml的PZA在3、5和7天的孵育期评估了该方法。M.还用标准韦恩测定法、四唑微量板测定法（特马）、Bactec 460 TB和pncA测序法检测了来自68个痰样品的结核菌株。我们比较了QW和标准韦恩试验与使用一致Bactec 460 TB和pncA测序的二分参考分类。结果：Wayne标准韦恩的敏感性为88%，特异性为97.5%，约登指数（YI）为0.855。在400 μ g/ml PZA时，QW在第7天显示最大YI为0.934，灵敏度为96%，特异性为97.4%。400 μ g/ml PZA的吸光度OD值比800 μ g/ml PZA更准确。虽然QW显示出较高的准确性PZA的敏感性，它没有定量与Bactec的百分比增长。特马测试是不可靠的，并没有与Bactec results.Conclusions相关：建议的QW测定是一种廉价的方法，能够提供标准化和自动化的比色PZA耐药性测试，具有更好的歧视比标准的韦恩测定。(C)2016由Elsevier Ltd.出版
Background: Pyrazinamide (PZA) is the most important drug against the latent stage of tuberculosis (TB) and is used in both first and second line treatment regimens. The continued increase in multi-drug resistant TB and the prevalence of PZA resistance makes the development of alternative assays for prompt identification of PZA resistance all the more important.Methods: We standardized and evaluated a quantitative variant of the Wayne assay (QW) for determining PZA resistance in Mycobacterium tuberculosis strains. This assay quantifies M. tuberculosis metabolism of PZA and production of pyrazinoic acid (POA) using visible spectrophotometry. We evaluated this method using PZA concentrations of 400 mu g/ml and 800 mu g/ml at incubation periods of 3, 5 and 7 days. M. tuberculosis strains from 68 sputum samples were also tested with the standard Wayne assay, Tetrazolium Microplate Assay (TEMA), Bactec 460TB and pncA sequencing. We compared QW and standard Wayne assay against a dichotomous reference classification using concordant Bactec 460TB and pncA sequencing. Secondarily, we determined the quantitative correlation between both QW values and TEMA's minimum inhibitory concentration (MIC) against Bactec 460TB percentage growth.Results: The standard Wayne showed sensitivity of 88% and specificity of 97.5%, giving a Youden Index (YI) of 0.855 against reference tests. The QW showed maximum YI of 0.934 on day 7 at 400 mu g/ml PZA with 96% sensitivity and 97.4% specificity. Absorbance OD values for 400 mu g/ml PZA were more accurate than 800 mu g/ml PZA. Although QW showed high accuracy for PZA susceptibility, it did not correlate quantitatively with Bactec percentage growth. TEMA testing was unreliable and did not correlate with Bactec results.Conclusions: The proposed QW assay is an inexpensive method capable of providing standardization and automation of colorimetric PZA resistance testing, with better discriminatory than the standard Wayne assay. (C) 2016 Published by Elsevier Ltd.