Division of Clinical Microbiology and Molecular Medicine, Department of Laboratory Medicine, All India Institute of Medical Sciences, New Delhi, India.
Division of Clinical Microbiology and Molecular Medicine, Department of Laboratory Medicine, All India Institute of Medical Sciences, New Delhi, India.
J Infect. 2017 Aug;75(2):125-131. doi: 10.1016/j.jinf.2017.04.010. Epub 2017 May 10.
Tuberculous meningitis (TBM) is the most severe form of extra-pulmonary tuberculosis (TB) due to association of diseases with high rates of mortality and morbidity. Diagnosis continues to be a clinical challenge as microbiological confirmation is rare and time consuming resulting in delayed treatment. Xpert MTB/RIF assay is a rapid and simple test, which has been endorsed by World Health Organization as an initial diagnostic test for the diagnosis of TBM. However, evidence still lacks for its performance on cerebrospinal fluid (CSF) for the diagnosis of TBM especially from India.
A total of 267 CSF samples from patients with high clinico-radiological suspicion of TBM were included in this study. Ziehl-Neelsen (ZN) staining, BACTEC Mycobacterial Growth Indicator Tube (MGIT-960) culture system, and Xpert MTB/RIF assay (using cartridge version G4) were tested on all samples.
Of total 267 samples, all were negative for smear AFB and 52 (19.5%) were culture positive by MGIT-960 culture system. However, out of 52 (19.5%) cultures detected positive by MGIT-960, 5 (9.6%) were detected as resistant to rifampicin. Xpert MTB/RIF assay was positive in 38 (14.2%) samples and negative in 223 (83.5%) samples. Cartridge error was detected in 6 (2.2%) samples, which could not be repeated due to insufficient sample volume. The sensitivity and specificity of Xpert MTB/RIF assay in comparison to MGIT-960 was 55.1% (95%, CI: 40.2-69.3) and 94.8% (95%, CI: 90.9-97.4) respectively. Overall, Xpert MTB/RIF assay detected 38 (14.2%) as positive for MTB of which 4 (10.5%), 31 (81.6%) and 3 (7.9%) were found to be rifampicin resistant, sensitive and indeterminate respectively.
Xpert MTB/RIF assay showed lower sensitivity as compared to MGIT 960 culture for the diagnosis of TBM from CSF samples.
结核性脑膜炎（TBM）是最严重的肺外结核（TB）形式，因为疾病与高死亡率和发病率有关。由于微生物学确认很少见且耗时，导致治疗延迟，因此诊断仍然是一个临床挑战。Xpert MTB/RIF 检测是一种快速而简单的检测方法，世界卫生组织已将其作为 TBM 诊断的初始诊断检测方法。然而，其在脑脊液（CSF）中用于诊断 TBM 的性能证据仍然缺乏，特别是来自印度的证据。
本研究共纳入 267 例临床疑似 TBM 高的 CSF 样本。所有样本均进行 Ziehl-Neelsen（ZN）染色、BACTEC 分枝杆菌生长指示管（MGIT-960）培养系统和 Xpert MTB/RIF 检测（使用试剂盒版本 G4）。
267 例标本中，所有 AFB 涂片均为阴性，52 例（19.5%）MGIT-960 培养阳性。然而，在 52 例（19.5%）培养阳性的标本中，有 5 例（9.6%）对利福平耐药。Xpert MTB/RIF 检测阳性 38 例（14.2%），阴性 223 例（83.5%）。6 例（2.2%）样本检测到试剂盒错误，由于样本量不足，无法重复。Xpert MTB/RIF 检测与 MGIT-960 相比，其敏感性和特异性分别为 55.1%（95%CI：40.2-69.3）和 94.8%（95%CI：90.9-97.4）。总的来说，Xpert MTB/RIF 检测发现 38 例（14.2%）MTB 阳性，其中 4 例（10.5%）、31 例（81.6%）和 3 例（7.9%）分别为利福平耐药、敏感和不确定。
与 MGIT 960 培养相比，Xpert MTB/RIF 检测在 CSF 样本中诊断 TBM 的敏感性较低。
