Detection and Quantification of Differentially Culturable Tubercle Bacteria in Sputum from Patients with Tuberculosis
Detection and Quantification of Differentially Culturable Tubercle Bacteria in Sputum from Patients with Tuberculosis
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DOI：
10.1164/rccm.201604-0769oc
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发表时间：
2016-12-15
影响因子：
24.7
通讯作者：
Kana, Bavesh D.
中科院分区：
文献类型：
--
作者：
Chengalroyen, Melissa D.;Beukes, Germar M.;Kana, Bavesh D.
基本原理：最近的研究表明，基线肺结核痰包括常规可培养和可分化培养的结节细菌(DCTB)的混合物。为了进一步探索这一点，我们对结核病患者的痰进行了DCTB的检测，并研究了外源培养滤液(CF)的体外补充对DCTB的影响。方法：用来自结核病和HIV-1的成人和非HIV-1成人的痰标本进行最可能数(MPN)检测，分别检测依赖于CF和RPF不依赖的DCTB。测量和主要结果：在110名个体中，19.1%的人存在依赖于CF的DCTB，没有RPF非依赖的DCTB。此外，11.8%产生RPF非依赖的DCTB，而不产生依赖于CF的DCTB。此外，53.6%的患者同时存在Cf依赖和RPF非依赖的DCTB，1.8%的患者携带Cf非依赖的DCTB，13.6%的患者没有DCTB。与感染HIV-1的人相比，没有感染HIV-1的人的痰中添加了CF的MPN数量更多。此外，与CD4计数低于200 cell/mm(3)的HIV-1患者相比，CD4计数大于200 cell/mm(3)的HIV-1患者显示出更高的补充CFMPN计数。Cf补充允许在34名固体培养上没有可培养细菌的患者中检测到分枝杆菌。结论：这些观察结果显示了痰中一种新的非RPF依赖的DCTB种群，并揭示了宿主免疫力降低与CF反应细菌的较低患病率有关。在标准的结核病诊断中量化DCTB将是有益的，因为这些微生物提供了一个假定的生物标记物来监测治疗反应和疾病复发的风险。
Rationale: Recent studies suggest that baseline tuberculous sputum comprises a mixture of routinely culturable and differentially culturable tubercle bacteria (DCTB). The latter seems to be drug tolerant and dependent on resuscitation-promoting factors (Rpfs).Objectives: To further explore this, we assessed sputum from patients with tuberculosis for DCTB and studied the impact of exogenous culture filtrate (CF) supplementation ex vivo.Methods: Sputum samples from adults with tuberculosis and HIV-1 and adults with no HIV-1 were used for most probable number (MPN) assays" supplemented with CF and Rpf-deficient CF, to detect CF-dependent and Rpf-independent DCTB, respectively.Measurements and Main Results: In 110 individuals, 19.1% harbored CF-dependent DCTB and no Rpf-independent DCTB. Furthermore, 11.8% yielded Rpf-independent DCTB with no CF dependent DCTB. In addition, 53.6% displayed both CF-dependent and Rpf-independent DCTB, 1.8% carried CF-independent DCTB, and 13.6% had no DCTB. Sputum from individuals without HIV-1 yielded higher CF-supplemented MPN counts compared with counterparts with HIV-1. Furthermore, individuals with HIV-1 with CD4 counts greater than 200 cells/mm(3) displayed higher CF supplemented MPN counts compared with participants with HIV-1 with CD4 counts less than 200 cells/mm(3). CF supplementation allowed for detection of mycobacteria in 34 patients with no culturable bacteria on solid media. Additionally, the use of CF enhanced detection of sputum smear-negative individuals.Conclusions: These observations demonstrate a novel Rpf-independent DCTB population in sputum and reveal that reduced host immunity is associated with lower prevalence of CF-responsive bacteria. Quantification of DCTB in standard TB diagnosis would be beneficial because these organisms provide a putative biomarker to monitor treatment response and risk of disease recurrence.