Department of Infection, Division of Infection and Immunity, University College London, London, UK.
Lancet Infect Dis. 2013 Jan;13(1):36-42. doi: 10.1016/S1473-3099(12)70245-1. Epub 2012 Nov 5.
Rapid and accurate diagnosis of pulmonary tuberculosis in children remains challenging because of difficulties in obtaining sputum samples and the paucibacillary nature of the disease. The Xpert MTB/RIF assay is useful for rapid diagnosis of childhood tuberculosis with sputum and nasopharyngeal samples. We assessed this assay for the detection of tuberculosis and multidrug resistant (MDR) tuberculosis with gastric lavage aspirate (GLA) samples in children admitted to hospital.
We did a prospective study to assess the sensitivity and specificity of the Xpert MTB/RIF assay with GLA samples for the detection of pulmonary tuberculosis and MDR tuberculosis in new paediatric inpatient admissions at the University Teaching Hospital, Lusaka, Zambia. Children aged 15 years or younger were recruited between June, 2011, and May, 2012. GLA and sputum were analysed by standard smear-microscopy, mycobacterial growth indicator tube (MGIT) culture, MGIT drug-susceptibility testing, and the Xpert MTB/RIF assay. Sensitivity of the Xpert MTB/RIF assay was assessed with the Pearson χ(2) or Fishers exact test.
Of 930 children, 142 produced sputum and GLA was obtained from 788 non-sputum producers. Culture-positive tuberculosis was identified in 58 (6·2%) of 930 children: ten from sputum producers and 48 from GLA of non-sputum producers. The sensitivity and specificity of the Xpert MTB/RIF assay were similar: sensitivity was 68·8% (95% CI 53·6-80·9) for GLA versus 90·0% (54·1-99·5; p=0·1649) for sputum samples; specificity was 99·3% (98·3-99·8) for GLA and 98·5% (94·1-99·7; p=0·2871) for sputum samples. The Xpert MTB/RIF assay detected an extra 28 tuberculosis cases compared with smear microscopy and was significantly more sensitive than smear microscopy for both sputum (90·0% [54·1-99·5] vs 30·0% [8·1-64·6], p=0·01) and GLA (68·8% [53·6-80·9] vs 25·0% [14·1-40·0], p<0·0001). The assay load did not differ significantly by sample type (p=0·791). 22 children were infected with HIV and tuberculosis and significant differences in assay performance could not be detected when stratifying by HIV status for either sample type. The Xpert MTB/RIF assay detected rifampicin resistance in three GLA samples: two confirmed as MDR tuberculosis and one false positive.
Analyses of GLA samples with the Xpert MTB/RIF assay is a sensitive and specific method for rapid diagnosis of pulmonary tuberculosis in children who cannot produce sputum. The single site nature of our study invites caution.
European Commission, European Developing Countries Clinical Trials Partnership, and UBS Optimus Foundation.
由于获取痰样本的困难和疾病的菌量少，儿童肺结核的快速准确诊断仍然具有挑战性。Xpert MTB/RIF 检测可用于快速诊断有痰和鼻咽样本的儿童结核病。我们评估了该检测方法对住院的儿童进行胃抽吸物（GLA）样本检测肺结核和耐多药（MDR）肺结核的效果。
我们进行了一项前瞻性研究，以评估 Xpert MTB/RIF 检测方法对赞比亚卢萨卡大学教学医院新入院的儿科住院患儿的 GLA 样本检测肺结核和 MDR 肺结核的敏感性和特异性。2011 年 6 月至 2012 年 5 月期间，招募了年龄在 15 岁或以下的儿童。通过标准涂片显微镜、分枝杆菌生长指示剂管（MGIT）培养、MGIT 药物敏感性试验和 Xpert MTB/RIF 检测方法对 GLA 和痰进行分析。Xpert MTB/RIF 检测方法的敏感性采用 Pearson χ(2)或 Fisher 确切检验进行评估。
在 930 名儿童中，142 名产生了痰，788 名非痰生产者获得了 GLA。在 930 名儿童中，有 58 名（6.2%）培养出结核分枝杆菌阳性：10 名来自痰生产者，48 名来自非痰生产者的 GLA。Xpert MTB/RIF 检测方法的敏感性和特异性相似：GLA 的敏感性为 68.8%（53.6-80.9），而痰样本的敏感性为 90.0%（54.1-99.5；p=0.1649）；GLA 的特异性为 99.3%（98.3-99.8），而痰样本的特异性为 98.5%（94.1-99.7；p=0.2871）。Xpert MTB/RIF 检测方法比涂片显微镜检测方法多检测到 28 例结核病病例，且在痰（90.0%[54.1-99.5]比 30.0%[8.1-64.6]，p=0.01）和 GLA（68.8%[53.6-80.9]比 25.0%[14.1-40.0]，p<0.0001）中都具有更高的敏感性。两种样本类型的检测负荷无显著差异（p=0.791）。22 名儿童感染了 HIV 和结核病，在对两种样本类型的 HIV 状态进行分层时，无法检测到检测性能的显著差异。Xpert MTB/RIF 检测方法在 3 个 GLA 样本中检测到利福平耐药：其中 2 个样本证实为 MDR 结核病，1 个为假阳性。
分析不能产生痰的儿童的 GLA 样本时，Xpert MTB/RIF 检测方法是一种快速诊断肺结核的敏感和特异性方法。我们的研究是单站点研究，其结果应谨慎对待。
欧盟委员会、欧洲发展中国家临床试验伙伴关系和 UBS Optimus 基金会。
