Tuberculosis Department, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing Chest Hospital, Capital Medical University, No 97, Machang, Tongzhou District, Beijing, 101149, People's Republic of China.
Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing Chest Hospital, Capital Medical University, No. 97, Machang, Tongzhou District, Beijing, 101149, China.
Infection. 2019 Aug;47(4):611-616. doi: 10.1007/s15010-019-01295-5. Epub 2019 Mar 23.
Stool is an alternative specimen matrix for tuberculosis (TB) tests, because Mycobacterium tuberculosis (MTB) can be swallowed and detected in the samples from digestive tract. We aimed to assess the performance of GeneXpert on stool and gastric lavage fluid (GALF) in diagnosing TB among patients with severe pulmonary TB.
We enrolled adults with suspected pulmonary TB who were unable to produce sputum at visit between January 2016 and June 2018. Bacteriological samples consisted of one transtracheal aspirate sputum specimen, one stool specimen and/or one gastric lavage fluid specimen. Bacterial culture of transtracheal aspirate sputum provided the gold standard.
Of 65 individuals recruited for analysis, MGIT culture identified the presence of MTB in 32 samples. Overall, 29 of 32 stool samples from culture-positive cases were detected by the GeneXpert test, demonstrating a sensitivity of 90.6%. For GALF, 13 patients were detected as infected with MTB by GeneXpert, yielding a sensitivity of 56.5%. The statistical analysis revealed that GeneXpert showed significantly better sensitivity in detecting MTB from stool samples than GALF samples (P = 0.003). Among individuals with GeneXpert-positive stool, the percentage of individuals with comorbid diabetes was significantly higher than among individuals with GeneXpert-negative stool (19.4% vs. 2.9%, P = 0.034).
In conclusion, our data reveal that GeneXpert provides a higher detection rate on stool compared to GALF, indicating stool should be considered as an alternative for adult TB patients unable to produce sputum. Individuals with diabetes are more likely to have positive GeneXpert stool than nondiabetic individuals.
粪便可作为结核病（TB）检测的替代样本基质，因为结核分枝杆菌（MTB）可被吞咽并在来自消化道的样本中被检测到。我们旨在评估 GeneXpert 在诊断严重肺结核患者中的粪便和胃洗液（GALF）中的表现。
我们招募了在 2016 年 1 月至 2018 年 6 月间就诊时无法产生痰液的疑似肺结核成人患者。细菌学样本包括一次经气管抽吸的痰标本、一次粪便标本和/或一次胃洗液标本。经气管抽吸的痰细菌培养为金标准。
在纳入分析的 65 名患者中，MGIT 培养在 32 个样本中发现 MTB 的存在。总体而言，在培养阳性病例的 32 个粪便样本中，29 个通过 GeneXpert 检测到，敏感性为 90.6%。对于 GALF，GeneXpert 检测到 13 例 MTB 感染，敏感性为 56.5%。统计分析显示，GeneXpert 在检测粪便样本中的 MTB 方面显示出明显更高的敏感性，与 GALF 样本相比（P=0.003）。在 GeneXpert 阳性粪便样本的个体中，患有合并糖尿病的个体比例明显高于 GeneXpert 阴性粪便样本的个体（19.4%比 2.9%，P=0.034）。
总之，我们的数据表明，与 GALF 相比，GeneXpert 在粪便中提供了更高的检测率，这表明粪便应被视为无法产生痰液的成人结核病患者的替代选择。患有糖尿病的个体比非糖尿病个体更有可能出现 GeneXpert 阳性粪便。
