Detection of Mycobacterium tuberculosis bacilli in bio-aerosols from untreated TB patients.
Detection of Mycobacterium tuberculosis bacilli in bio-aerosols from untreated TB patients.
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DOI：
10.12688/gatesopenres.12758.1
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发表时间：
2017-11-07
影响因子：
--
通讯作者：
Wood, Robin
中科院分区：
文献类型：
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作者：
Patterson, Benjamin;Morrow, Carl;Wood, Robin
背景：结核病（TB）主要是一种空气传播疾病。然而，含有病原体结核分枝杆菌（Mtb）的生物气溶胶的定量和定性分析已被证明是非常具有挑战性的。我们的目标是从新诊断的结核病患者身上采集生物气溶胶样本，用于检测和计数结核分枝杆菌。方法：我们在定制的呼吸气溶胶采样室（RASC）中监测了35名新诊断的GeneXpert结核阳性TB患者1小时的隔离期。RASC（一个1.4米的小型洁净室）包括空气动力学颗粒尺寸检测、活性和非活性采样装置、实时二氧化碳监测和咳嗽录音。使用微生物培养和液滴数字聚合酶链反应（ddPCR）检测每个生物气溶胶收集装置中的结核分枝杆菌。结果如下：27/35（77.1%）的气溶胶样品中检测到Mtb; 15/35（42.8%）的样品通过分枝杆菌培养而阳性，25/27（92.96%）的样品通过ddPCR而阳性。肺空洞、痰涂片阳性或咳嗽率的影像学证据不能预测所收集的杆菌的培养能力。在所有可行的级联撞击采样器级上检测到结核分枝杆菌，在气溶胶尺寸2.0- 3.5 μ m处达到峰值。这表明气溶胶培养阳性的呼出气中位值为0.09 CFU/L（IQR：0.07 - 0.3 CFU/L），呼出微粒生物气溶胶的估计中位浓度为4.5x10 CFU/ml（IQR：2.9x10 - 5.6x10）。结论：使用RASC在大多数未经治疗的结核病患者呼出的生物气溶胶中鉴定出结核分枝杆菌。分子检测比固体培养基上的分枝杆菌培养更敏感，这表明需要进一步的研究来确定这是否反映了这些样品中差异可检测的杆菌的显著比例。
Background:Tuberculosis (TB) is predominantly an airborne disease. However, quantitative and qualitative analysis of bio-aerosols containing the aetiological agent, Mycobacterium tuberculosis (Mtb), has proven very challenging. Our objective is to sample bio-aerosols from newly diagnosed TB patients for detection and enumeration of Mtb bacilli. Methods:We monitored each of 35 newly diagnosed, GeneXpert sputum-positive, TB patients during 1 hour confinement in a custom-built Respiratory Aerosol Sampling Chamber (RASC). The RASC (a small clean-room of 1.4m ) incorporates aerodynamic particle size detection, viable and non-viable sampling devices, real-time CO 2 monitoring, and cough sound-recording. Microbiological culture and droplet digital polymerase chain reaction (ddPCR) were used to detect Mtb in each of the bio-aerosol collection devices. Results: Mtb was detected in 27/35 (77.1%) of aerosol samples; 15/35 (42.8%) samples were positive by mycobacterial culture and 25/27 (92.96%) were positive by ddPCR. Culturability of collected bacilli was not predicted by radiographic evidence of pulmonary cavitation, sputum smear positivity, or cough rate. Mtb was detected on all viable cascade impactor stages with a peak at aerosol sizes 2.0-3.5mum. This suggests a median of 0.09 CFU/litre of exhaled air (IQR: 0.07 to 0.3 CFU/l) for the aerosol culture positives and an estimated median concentration of 4.5x10 CFU/ml (IQR: 2.9x10 -5.6x10 ) of exhaled particulate bio-aerosol. Conclusions: Mtb was identified in bio-aerosols exhaled by the majority of untreated TB patients using the RASC. Molecular detection was more sensitive than mycobacterial culture on solid media, suggesting that further studies are required to determine whether this reflects a significant proportion of differentially detectable bacilli in these samples.