Containment of Bioaerosol Infection Risk by the Xpert MTB/RIF Assay and Its Applicability to Point-of-Care Settings
Containment of Bioaerosol Infection Risk by the Xpert MTB/RIF Assay and Its Applicability to Point-of-Care Settings
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DOI：
10.1128/jcm.01053-10
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发表时间：
2010-10-01
影响因子：
9.4
通讯作者：
Alland, David
中科院分区：
文献类型：
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作者：
Banada, Padmapriya P.;Sivasubramani, Satheesh K.;Alland, David
最近引进的Xpert MTB/RIF分析(Xpert)具有医疗保健的潜力，但其控制生物危害的能力仍有待研究。我们将Xpert试验产生的生物气溶胶与抗酸杆菌(AFB)显微镜玻片涂片进行了比较。对XPERT分析样品处理试剂(SR)的杀菌能力、稳定性以及长期处理对测定灵敏度的影响进行了研究。在AFB涂片的制备过程中，用5×10(8)cfu/ml的牛分枝杆菌BCG添加的痰标本分别产生16和325 cfu/m(3)的空气，用Andersen撞击仪或生物采样器测量。相比之下，Xpert化验的样品制备步骤及其自动化处理都没有产生任何可培养的生物气雾剂。在SR灭菌能力的测试中，以2：1的比例使用SR治疗的强涂阳肺结核患者的临床痰标本，除1/39和3/45的标本在固体或液体培养上培养外，其余均可消除结核分枝杆菌的生长。这些少数未灭菌的样本在培养阳性的时间上平均延迟了13.1天。3：1比例的SR处理消除了所有样品中的生长。尽管在4至45摄氏度的温度下储存了至少3个月，SR仍保持着超过6个对数单位的杀灭能力。并对延长SR样品处理时间的效果进行了研究。添加的痰样本可以在SR中孵育长达3天，而不影响Xpert检测结核分枝杆菌的敏感性，最长可孵育8小时，而不影响利福平耐药性检测的特异性。这些结果表明，台式使用Xpert MTB/RIF检测限制了用户的感染风险。
The recently introduced Xpert MTB/RIF assay (Xpert) has point-of-care potential, but its capacity for biohazard containment remained to be studied. We compared the bioaerosols generated by the Xpert assay to acid-fast bacillus (AFB) microscope slide smear preparation. The Xpert assay sample treatment reagent (SR) was also studied for its sterilizing capacity, stability, and effect on assay sensitivity after prolonged treatment. During the preparation of AFB smears, sputum samples spiked with Mycobacterium bovis BCG at 5 x 10(8) CFU/ml produced 16 and 325 CFU/m(3) air measured with an Andersen impactor or BioSampler, respectively. In contrast, neither the sample preparation steps for the Xpert assay nor its automated processing produced any culturable bioaerosols. In testing of SR sterilizing capacity, clinical sputum samples from strongly smear-positive tuberculosis patients treated with SR at a 2: 1 ratio eliminated Mycobacterium tuberculosis growth in all but 1/39 or 3/45 samples cultured on solid or liquid medium, respectively. These few unsterilized samples had a mean 13.1-day delay in the time to positive culture. SR treatment at a 3: 1 ratio eliminated growth in all samples. SR retained a greater than 6-log-unit killing capacity despite storage at temperatures spanning 4 to 45 degrees C for at least 3 months. The effect of prolonged SR sample treatment was also studied. Spiked sputum samples could be incubated in SR for up to 3 days without affecting Xpert sensitivity for M. tuberculosis detection and up to 8 h without affecting specificity for rifampin resistance detection. These results suggest that benchtop use of the Xpert MTB/RIF assay limits infection risk to the user.