Lore Michael B, Heimbuch Brian K, Brown Teanne L, Wander Joseph D, Hinrichs Steven H
Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198, USA.
Ann Occup Hyg. 2012 Jan;56(1):92-101. doi: 10.1093/annhyg/mer054. Epub 2011 Aug 22.
Filtering facepiece respirators (FFRs) are recommended for use as precautions against airborne pathogenic microorganisms; however, during pandemics demand for FFRs may far exceed availability. Reuse of FFRs following decontamination has been proposed but few reported studies have addressed the feasibility. Concerns regarding biocidal efficacy, respirator performance post decontamination, decontamination cost, and user safety have impeded adoption of reuse measures. This study examined the effectiveness of three energetic decontamination methods [ultraviolet germicidal irradiation (UVGI), microwave-generated steam, and moist heat] on two National Institute for Occupational Safety and Health-certified N95 FFRs (3M models 1860s and 1870) contaminated with H5N1. An aerosol settling chamber was used to apply virus-laden droplets to FFRs in a method designed to simulate respiratory deposition of droplets onto surfaces. When FFRs were examined post decontamination by viral culture, all three decontamination methods were effective, reducing virus load by > 4 log median tissue culture infective dose. Analysis of treated FFRs using a quantitative molecular amplification assay (quantitative real-time polymerase chain reaction) indicated that UVGI decontamination resulted in lower levels of detectable viral RNA than the other two methods. Filter performance was evaluated before and after decontamination using a 1% NaCl aerosol. As all FFRs displayed <5% penetration by 300-nm particles, no profound reduction in filtration performance was caused in the FFRs tested by exposure to virus and subsequent decontamination by the methods used. These findings indicate that, when properly implemented, these methods effectively decontaminate H5N1 on the two FFR models tested and do not drastically affect their filtering function; however, other considerations may influence decisions to reuse FFRs.
过滤式面罩呼吸器（FFR）被推荐用于预防空气传播的致病微生物；然而，在大流行期间，FFR的需求可能远远超过供应。有人提议对FFR进行去污后再使用，但很少有报道的研究涉及其可行性。对杀菌效果、去污后面罩呼吸器的性能、去污成本和使用者安全的担忧阻碍了再利用措施的采用。本研究考察了三种强力去污方法[紫外线杀菌照射（UVGI）、微波产生的蒸汽和湿热]对两种经美国国家职业安全与健康研究所认证的、被H5N1污染的N95 FFR（3M 1860s型和1870型）的有效性。使用气溶胶沉降室以一种旨在模拟呼吸道飞沫在表面沉积的方法将载有病毒的飞沫施加到FFR上。当通过病毒培养对去污后的FFR进行检测时，所有三种去污方法均有效，病毒载量降低超过4个对数中位组织培养感染剂量。使用定量分子扩增测定法（定量实时聚合酶链反应）对处理后的FFR进行分析表明，UVGI去污导致可检测到的病毒RNA水平低于其他两种方法。在去污前后使用1% NaCl气溶胶对面罩呼吸器的过滤性能进行评估。由于所有FFR对300纳米颗粒的穿透率均<5%，因此通过所使用的方法对FFR进行病毒暴露和随后的去污处理后，其过滤性能没有显著降低。这些发现表明，当正确实施时，这些方法能有效去除测试的两种FFR模型上的H5N1，且不会大幅影响其过滤功能；然而，其他因素可能会影响FFR再利用的决策。
