背景:结核病(TB)的早期诊断和普遍获得药物敏感性测试(DST)是WHO终结结核病战略的关键要素。当前的快速测试(例如,Xpert®MTB/RIF和Ultra-分析)可以检测利福平抗性突变,但无法检测到对异烟肼和二线抗结核药物的耐药性。尽管线探针测定法能够检测对二线抗结核剂的抗性,它需要复杂的实验室基础设施和先进的技能,而这些技能在结核病充斥的环境中往往不容易获得。非常需要能够检测异烟肼和二线抗结核药物耐药性的快速测试。
方法:我们进行了一项诊断准确性研究,以评估一种新的自动XpertMTB/XDR10色测定法,用于快速检测异烟肼和二线药物,包括乙二甲酰胺,氟喹诺酮类药物,和可注射药物(阿米卡星,卡那霉素,和卷曲霉素)。在坦桑尼亚的中央结核病参考实验室,通过常规诊断和耐药性监测,前瞻性收集了阳性XpertMTB/RIF呼吸道标本。通过XpertXDR测定和LPA针对基于培养的表型DST作为参考标准来测试样本。
结果:我们分析了151例TB患者的样本,平均年龄(SD)为36.2(12.7)岁。大多数(n=109,72.2%)是男性。XpertMTB/XDR的敏感性为93.5%(95%CI,87.4-96.7);异烟肼,96.6(95%CI,92.1-98.6);对于氟喹诺酮,98.7%(95%Cl94.8-99.7);阿米卡星,96.6%;乙二酰胺(95%CI92.1-98.6)。对于氟喹诺酮,埃塞俄比亚酰胺的特异性最低,为50%,最高为100%。诊断性能通常与LPA相当,在两种测定之间有轻微的变化。非确定率(即,结核分枝杆菌复合物检测无效)的XpertMTB/XDR为2·96%。
结论:XpertMTB/XDR在检测异烟肼耐药性方面表现出很高的敏感性和特异性,氟喹诺酮类药物,和注射剂。该测定可用于临床环境中以促进单异烟肼和广泛耐药TB的快速诊断。
BACKGROUND: Early diagnosis of tuberculosis (TB) and universal access to drug-susceptibility testing (DST) are critical elements of the WHO End TB Strategy. Current rapid tests (e.g., Xpert® MTB/RIF and Ultra-assays) can detect rifampicin resistance-conferring mutations, but cannot detect resistance to Isoniazid and second-line anti-TB agents. Although Line Probe Assay is capable of detecting resistance to second-line anti-TB agents, it requires sophisticated laboratory infrastructure and advanced skills which are often not readily available in settings replete with TB. A rapid test capable of detecting Isoniazid and second-line anti-TB drug resistance is highly needed.
METHODS: We conducted a diagnostic accuracy study to evaluate a new automated Xpert MTB/XDR 10-colour assay for rapid detection of Isoniazid and second-line drugs, including ethionamide, fluoroquinolones, and injectable drugs (Amikacin, Kanamycin, and Capreomycin). Positive Xpert MTB/RIF respiratory specimens were prospectively collected through routine diagnosis and surveillance of drug resistance at the Central TB Reference Laboratory in Tanzania. Specimens were tested by both Xpert XDR assay and LPA against culture-based phenotypic DST as the reference standard.
RESULTS: We analysed specimens from 151 TB patients with a mean age (SD) of 36.2 (12.7) years. The majority (n = 109, 72.2%) were males. The sensitivity for Xpert MTB/XDR was 93.5% (95% CI, 87.4-96.7); for Isoniazid, 96.6 (95% CI, 92.1-98.6); for Fluoroquinolone, 98.7% (95% Cl 94.8-99.7); for Amikacin, 96.6%; and (95% CI 92.1-98.6) for Ethionamide. Ethionamide had the lowest specificity of 50% and the highest was 100% for Fluoroquinolone. The diagnostic performance was generally comparable to that of LPA with slight variations between the two assays. The non-determinate rate (i.e., invalid M. tuberculosis complex detection) of Xpert MTB/XDR was 2·96%.
CONCLUSIONS: The Xpert MTB/XDR demonstrated high sensitivity and specificity for detecting resistance to Isoniazid, Fluoroquinolones, and injectable agents. This assay can be used in clinical settings to facilitate rapid diagnosis of mono-isoniazid and extensively drug-resistant TB.