National Institute for Occupational Safety and Health, National Personal Protective Technology Laboratory, Pittsburgh, PA 15236, USA.
Appl Environ Microbiol. 2009 Dec;75(23):7303-9. doi: 10.1128/AEM.00799-09. Epub 2009 Oct 2.
The aim of this study was to develop a test system to evaluate the effectiveness of procedures for decontamination of respirators contaminated with viral droplets. MS2 coliphage was used as a surrogate for pathogenic viruses. A viral droplet test system was constructed, and the size distribution of viral droplets loaded directly onto respirators was characterized using an aerodynamic particle sizer. The sizes ranged from 0.5 to 15 mum, and the sizes of the majority of the droplets were the range from 0.74 to 3.5 mum. The results also showed that the droplet test system generated similar droplet concentrations (particle counts) at different respirator locations. The test system was validated by studying the relative efficiencies of decontamination of sodium hypochlorite (bleach) and UV irradiation with droplets containing MS2 virus on filtering facepiece respirators. It was hypothesized that more potent decontamination treatments would result in corresponding larger decreases in the number of viable viruses recovered from the respirators. Sodium hypochlorite doses of 2.75 to 5.50 mg/liter with a 10-min decontamination period resulted in approximately 3- to 4-log reductions in the level of MS2 coliphage. When higher sodium hypochlorite doses (> or =8.25 mg/liter) were used with the same contact time that was used for the dilute solutions containing 2.75 to 5.50 mg/liter, all MS2 was inactivated. For UV decontamination at a wavelength of 254 nm, an approximately 3-log reduction in the level of MS2 virus was achieved with dose of 4.32 J/cm(2) (3 h of contact time with a UV intensity of 0.4 mW/cm(2)), while with higher doses of UV irradiation (> or =7.20 J/cm(2); UV intensity, 0.4 mW/cm(2); contact times, > or =5 h), all MS2 was inactivated. These findings may lead to development of a standard method to test decontamination of respirators challenged by viral droplets.
本研究旨在开发一种测试系统，以评估针对受病毒液滴污染的呼吸器的消毒程序的效果。MS2 噬菌体被用作致病病毒的替代品。构建了一个病毒液滴测试系统，并使用空气动力学颗粒粒径仪对直接加载到呼吸器上的病毒液滴的粒径分布进行了表征。粒径范围为 0.5 至 15 µm，其中大部分液滴的粒径范围为 0.74 至 3.5 µm。结果还表明，在不同的呼吸器位置，液滴测试系统产生了相似的液滴浓度（颗粒计数）。通过研究含 MS2 病毒的液滴对过滤式面罩呼吸器的消毒效果，验证了该测试系统的有效性。假设更有效的消毒处理会导致从呼吸器上回收的活病毒数量相应减少。含氯消毒剂（漂白剂）剂量为 2.75 至 5.50 毫克/升，消毒时间为 10 分钟，可使 MS2 噬菌体的水平降低约 3 至 4 对数级。当使用更高剂量的含氯消毒剂（>或=8.25 毫克/升），且接触时间与含 2.75 至 5.50 毫克/升的稀释溶液相同，所有 MS2 都被灭活。对于波长为 254nm 的紫外线消毒，剂量为 4.32 J/cm2（接触时间为 3 小时，紫外线强度为 0.4mW/cm2）时，MS2 病毒的水平降低约 3 对数级，而当紫外线照射剂量较高（>或=7.20 J/cm2；紫外线强度，0.4mW/cm2；接触时间，>或=5 小时）时，所有 MS2 都被灭活。这些发现可能会导致开发出一种标准方法来测试受病毒液滴挑战的呼吸器的消毒效果。
