Preservation of sputum samples with cetylpyridinium chloride (CPC) for tuberculosis cultures and Xpert MTB/RIF in a low-income country
Preservation of sputum samples with cetylpyridinium chloride (CPC) for tuberculosis cultures and Xpert MTB/RIF in a low-income country
复制标题
DOI：
10.1186/s12879-017-2642-z
复制
发表时间：
2017-08-04
影响因子：
3.7
通讯作者：
Fenner, Lukas
中科院分区：
文献类型：
--
作者：
Hiza, Hellen;Doulla, Basra;Fenner, Lukas
背景：环境细菌的培养污染是炎热潮湿气候区结核病（TB）实验室面临的主要挑战。方法：收集痰涂片镜检阳性的结核病患者痰标本，采用免疫组化法检测结核分枝杆菌耐药菌株，并分析CPC保存液对结核分枝杆菌耐药菌株培养结果和Xpert MTB/RIF检测性能的影响。将200份样品平均分成两等份，其中一等份用CPC处理，并在环境温度下储存7天。立即处理第二份等分试样。将样品净化20、15或10分钟，随后在Lowenstein-Jensen培养基上培养。此外，将50份样本储存7、14和21天，并通过Xpert MTB/RIF检测100份CPC预处理样本。结果：在所有去污时间内，CPC预处理样本的培养产量均高于未处理痰液样本：10分钟时94%对73%（p = 0.01），15分钟时94%对64%（p = 0.004），20分钟时90%对52%（p < 0.001）。定量培养分级在CPC处理的样品中始终高于非CPC处理的样品。在所有去污时间内，CPC预处理样品中污染培养物的比例（范围2-6%）低于非CPC处理样品（15-16%）。对于CPC处理的样品的7、14和21天的储存时间，84、86和84%的相应培养物为阳性。在91份CPC处理的阳性培养样本中，90份也为Xpert MTB/RIF阳性。结论：CPC增加了培养产量，降低了污染比例，并且不会改变Xpert MTB/RIF的性能。
Background: Culture contamination with environmental bacteria is a major challenge in tuberculosis (TB) laboratories in hot and humid climate zones. We studied the effect of cetylpyridinium chloride (CPC) preservation on culture results and performance of Xpert MTB/RIF.Methods: Consecutive sputum samples from microscopy smear-positive TB patients were collected. Two-hundred samples were equally split in two aliquots, one aliquot was treated with CPC and stored at ambient temperature for 7 days. The second aliquot was immediately processed. Samples were decontaminated for 20, 15 or 10 min, and subsequently cultured on Lowenstein-Jensen medium. Furthermore, 50 samples were stored for 7, 14 and 21 days, and 100 CPC-pretreated samples tested by Xpert MTB/RIF.Results: CPC pretreated samples showed a higher culture yield compared to non-treated sputum samples across all decontamination times: 94% vs. 73% at 10 min (p = 0.01), 94% vs. 64% at 15 min (p = 0.004), and 90% vs. 52% at 20 min (p < 0.001). The quantitative culture grading was consistently higher in CPC treated compared to non-CPC treated samples. The proportion of contaminated cultures was lower in CPC pretreated samples across all decontamination times (range 2-6%) compared to non-CPC treated samples (15-16%). For storage times of CPC treated samples of 7, 14, and 21 days, 84, 86, and 84% of the respective cultures were positive. Of 91 CPC treated samples with a positive culture, 90 were also Xpert MTB/RIF positive.Conclusions: CPC increases culture yield, decreases the proportion of contamination, and does not alter the performance of Xpert MTB/RIF.