infection control & hospital epidemiology october 2015, vol. 36, no. 10 concise communication


The Ebola Disinfection Booth: Evaluation of an Enclosed Ultraviolet Light Booth for Disinfection of Contaminated Personal Protective Equipment Prior to Removal


Myreen E. Tomas, MD;1 Jennifer L. Cadnum, BS;2 Annette Jencson, CIC;3 Curtis J. Donskey, MD1,4


A portable booth designed to disinfect full-body coverage protective equipment before removal using ultraviolet-C radiation resulted in at least 3 log reductions in bacteriophage MS2 and methicillin-resistant Staphylococcus aureus within 3 minutes. The booth could be useful for disinfection of contaminated protective equipment before removal during care of Ebola patients.


Infect. Control Hosp. Epidemiol. 2015;36(10):1226–1228 methods


The Daylight Disinfection Suite is a portable 4.5 ft deep×4.5 ft wide × 7.5 ft tall rectangular booth with an inner reflective surface that delivers UV-C radiation via 4 low-pressure UV-C lamps. The booth is designed to allow personnel wearing full- body coverage protective equipment to stand inside while the system disinfects outer equipment prior to removal. The maximal distance from the UV-C lamps is 2 feet at the center of the booth, and contaminated sites can be placed close to the lamps. We examined the efficacy of the booth for killing micro- organisms inoculated on sections of gloves or gowns and on steel disks. The test organisms included bacteriophage MS2 (American Type Culture Collection 15597-B1), a non- pathogenic surrogate for small RNA viruses such as Ebola8; and a clinical methicillin-resistant Staphylococcus aureus (MRSA) isolate from pulsed-field gel electrophoresis type USA300. Bacteriophage MS2 was propagated in Escherichia coli 15597 as previously described.8 For MRSA, testing was performed in the presence or absence of 5% fetal calf serum. Ten μL of phosphate-buffered saline or 5% fetal calf serum


Contamination of the skin and clothing of healthcare personnel may occur during removal of personal protective equipment (PPE).1 Such contamination may place healthcare personnel at risk, as illustrated by recent cases in which Ebola virus infection was acquired despite use of PPE.2 To reduce the risk for contamination during care of patients with suspected or confirmed Ebola virus infection, the Centers for Disease Control and Prevention have recommended disinfection of gloves at multiple steps during PPE doffing.3 Disinfection of other protective equipment with a disinfectant wipe or spray is recommended if visible contamination is present. However, pathogen contamination often occurs without visible soiling and application of effective quantities of liquid disinfectants to equipment such as gowns and face shields may not be feasible.4 Ultraviolet C (UV-C) irradiation is effective in killing


viruses, including Ebola, and may be more effective against enveloped viruses such as Ebola than against nonenveloped viruses. 5–6 In a previous study, a pulsed xenon UV room disinfection unit was effective in reducing a nonenveloped canine parvovirus on PPE.7 However, room disinfection units do not provide an ideal method to deliver UV-C for PPE dis- infection. The Daylight Disinfection Suite Model 1077-02 (Daylight Medical) is a novel, portable UV-C disinfection booth designed for disinfection of full-body coverage PPE prior to removal. Here, we tested the efficacy of the booth for reduction of microorganisms inoculated onto PPE and used photochromic detection strips to assess whether UV-C penetrated through PPE.


containing bacteriophage MS2 or MRSA was inoculated onto 1-cm2 sections of gloves and gowns and on 1-cm2 steel disks; the carriers were affixed to glass microscope slides. For each organism, the inoculum applied to the carriers was adjusted such that 5 to 6 log10 colony-forming units/cm2 were recov- ered from untreated controls. The carriers were positioned vertically at a height of 4 feet inside the booth at distances of 6 inches from one bulb or in the center of the booth at 2 feet from each of the 4 bulbs; for a subset of experiments, carriers were placed 2 feet from the bulbs at heights of 1, 2, 4, and 6 feet within the booth. The organisms were treated for 30 seconds or 1, 3, or 5 minutes. The carriers were each submersed in 1 mL of phosphate-buffered saline and vortexed for 1 minute; dilutions were plated onto selective media and enumerated as previously described.8–9 Following 24 hours of incubation for bacteriophage and 48 hours for MRSA, log10 plaque-forming unit or colony-forming unit reductions were calculated by comparing the recovery after UV-C disinfection with untreated controls. Similar experimentswere conducted in which the pathogens


were inoculated onto a face shield and Tyvek coverall (DuPont) at the wrist, elbow, shoulder, chest, waist, knee, and ankle; the suit was suspended to mimic the position of a healthcare worker standing in the center of the UV-C booth and treated for 5 minutes. The suit and face mask were sam- pled using premoistened swabs and processed as described previously. All experiments were performed in triplicate. Data were analyzed using R, version 3.1.1. To assess penetration of UV-C through PPE, we placed UV-C photochromatic detection strips (Daylight Medical) on


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