Detection of Mycobacterium tuberculosis complex organisms in the stools of patients with pulmonary tuberculosis
Detection of Mycobacterium tuberculosis complex organisms in the stools of patients with pulmonary tuberculosis
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DOI：
10.1099/mic.0.026484-0
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发表时间：
2009-07-01
期刊：
影响因子：
2.8
通讯作者：
Drancourt, Michel
中科院分区：
文献类型：
--
作者：
El Khechine, Amel;Henry, Mireille;Drancourt, Michel
肺结核的实验室诊断主要依靠痰液中结核分枝杆菌复合体（MTC）的检测。对于不咳痰的患者，只能通过侵入性手术获得其他呼吸道标本。基于已知的MTC生物在胃液中的存活，我们假设在粪便样本中可以检测到吞咽的MTC生物。我们比较了同一患者呼吸道标本和粪便标本中MTC生物的存在。在适当去污后、Ziehl-Neelsen染色后镜检和内部对照IS6110实时PCR检测的蛋基培养基培养物中检测MTC。肺结核病例的定义是：(i)临床和放射学体征和症状提示肺结核，（ii）从至少一个呼吸道标本中培养出MTC有机体，或（iii）痰中存在抗酸杆菌，随后通过实时PCR鉴定为MTC有机体。通过对134例疑似肺结核患者的观察，鉴定出24例和110例未感染对照。病例和对照组在性别方面没有显著差异，但病例明显比对照组年轻。显微镜检查粪便的敏感性/特异性为37.5%/100%，培养敏感性/特异性为54.2%/100%，实时PCR敏感性/特异性为100%/97.3%。阳性预测值分别为100%、100%和88.9%，阴性预测值分别为88%、90.9%和100%。在4例患者中，粪便标本最初被正确诊断为肺结核，随后呼吸道标本的评估证实了诊断。这些数据表明，粪便可与痰液检测结合使用，或作为通过抗酸杆菌分子鉴定和培养诊断肺结核的替代标本。这种非侵入性的替代程序对不能咳痰的患者特别感兴趣。
The laboratory diagnosis of pulmonary tuberculosis mainly relies on the detection of Mycobacterium tuberculosis complex (MTC) organisms in the sputum. In patients who do not give sputum, alternative respiratory tract specimens can be obtained only by invasive procedures. Based on the known survival of MTC organisms in the gastric fluid, we hypothesized that swallowed MTC organisms would be detectable in stool samples. We compared the presence of MTC organisms in respiratory tract specimens and stool specimens collected in parallel from the same patients. MTC was detected in cultures grown on egg-based medium after appropriate decontamination, by microscopic examination after Ziehl-Neelsen staining and by real-time PCR detection of IS6110 using internal controls. A case of pulmonary tuberculosis was defined by the presence of (i) clinical and radiological signs and symptoms suggestive of pulmonary tuberculosis, and (ii) culture of MTC organisms from at least one respiratory tract specimen or (iii) the presence of acid-fast bacilli in the sputum that were subsequently identified as MTC organisms by real-time PCR. The observation of 134 patients suspected to be suffering pulmonary tuberculosis led to the identification of 24 cases and 110 non-infected control patients. Cases and controls did not significantly differ with respect to sex but cases were significantly younger than controls. The sensitivity/specificity was 37.5%/100% for the microscopic examination of stools, 54.2%/100% for culturing and 100%/97.3% for real-time PCR. The positive predicted value was 100%, 100% and 88.9%, respectively, and the negative predicted value was 88%, 90.9% and 100%,respectively. In four patients, a stool specimen initially yielded the correct diagnosis of pulmonary tuberculosis before evaluation of the respiratory tract specimen confirmed the diagnosis. These data indicate that stools could be used in conjunction with sputum testing or as an alternative specimen upon which to base the diagnosis of pulmonary tuberculosis by molecular identification of acid-fast bacilli and culture. This non-invasive alternative procedure is of particular interest for patients who cannot expectorate.