Zargar B, Sattar S A, Rubino J R, Ijaz M K
CREM Co Labs, Units 1-2, 3403 American Drive, Mississauga, ON, Canada.
Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada.
Lett Appl Microbiol. 2019 Mar;68(3):206-211. doi: 10.1111/lam.13109. Epub 2019 Jan 21.
Indoor air can spread pathogens, which can be removed/inactivated by a variety of means in healthcare and other settings. We quantitatively assessed if air decontamination could also simultaneously reduce environmental surface contamination in the same setting. Two types of vegetative bacteria (Staphylococcus aureus and Acinetobacter baumannii), and a bacterial spore-former (Geobacillus stearothermophilus) were tested as representative airborne bacteria. They were separately aerosolized with a Collison nebulizer into a 24-m aerobiology chamber and air samples collected with a programmable slit-to-agar sampler. Settling airborne particles were collected on culture plates placed at, and collected from, five different locations on the floor of the chamber with a custom-built remote plate-placement and -retriever system. Experimentally contaminated air in the chamber was decontaminated for 45 min with a device based on HEPA filtration and UV light. The plates were incubated and CFU counted. The device reduced the viability levels of all tested bacteria in the air by >3 log (>99·9%) in 45 min. Based on two separate tests, the average reductions in surface contamination for S. aureus, A. baumannii and G. stearothermophilus were respectively, 97, 87 and 97%. We thus showed that air decontamination could substantially and simultaneously reduce the levels of surface contamination in the same setting irrespective of the type of pathogen present. SIGNIFICANCE AND IMPACT OF THE STUDY: The innovative and generic test protocol described can quantitatively assess the reduction in environmental surface contamination from microbial decontamination of indoor air in the same setting. This added advantage from air decontamination has implications for infection prevention and control in healthcare and other settings without the need for additional expense or effort. Continuous operation of an air decontamination device, such as the one tested here, can lead to ongoing reductions in pathogens in air and on environmental surfaces.
室内空气可传播病原体，在医疗保健和其他场所，可通过多种方式将其清除/灭活。我们定量评估了空气净化是否也能在同一环境中同时减少环境表面污染。选取两种营养型细菌（金黄色葡萄球菌和鲍曼不动杆菌）以及一种产芽孢细菌（嗜热栖热放线菌）作为代表性空气传播细菌进行测试。使用科里森雾化器将它们分别雾化到一个24米的空气生物学试验舱中，并用可编程狭缝-琼脂采样器采集空气样本。通过定制的远程平板放置和取回系统，将沉降的空气颗粒收集在放置于试验舱地板五个不同位置的培养皿上，并从这些位置收集培养皿。使用基于高效空气过滤器和紫外线的设备对试验舱内受实验污染的空气进行45分钟的净化处理。将培养皿进行培养并计算菌落形成单位（CFU）。该设备在45分钟内将空气中所有测试细菌的活力水平降低了超过3个对数（>99.9%）。基于两项独立测试，金黄色葡萄球菌、鲍曼不动杆菌和嗜热栖热放线菌表面污染的平均减少率分别为97%、87%和97%。因此，我们表明，无论存在何种病原体类型，空气净化均可在同一环境中大幅且同时降低表面污染水平。研究的意义和影响：所描述的创新通用测试方案可定量评估同一环境中室内空气微生物净化对环境表面污染减少的情况。空气净化带来的这一额外优势对医疗保健和其他场所的感染预防与控制具有重要意义，且无需额外费用或努力。持续运行此处测试的空气净化设备，可使空气中和环境表面的病原体持续减少。
