ppe disinfection using a uv-c booth 1227
the inner surface of gloves, gowns, and face shields during exposure for 5 minutes and evaluated for color change indi- cating UV-C exposure.
results
As shown in Figure 1, the UV-C disinfection booth reduced recovery of bacteriophage MS2 and MRSA with greater reductions occurring with increased exposure time and closer proximity to the UV-C lamps. A reduction in both pathogens of 3 or more log10 colony-forming units was achieved in 1 minute at 6 inches from a UV-C lamp and in 3 minutes at 2 ft from the lamps. The efficacy of the UV-C disinfection booth was not significantly reduced by the presence of 5% fetal calf serum or by placement at different heights within the booth (data not shown). On the face shield and Tyvek suit, a 5-minute exposure resulted in a reduction in MRSA of 4 or more log10 colony-forming units and a reduction in bacter- iophage MS2 of 5 or more log10 plaque-forming units at all inoculation sites. Photochromatic detection strips demon- strated no evidence of UV-C penetration of PPE materials during 5 minutes of exposure.
discussion
The UV-C disinfection booth reduced recovery of bacter- iophage MS2 and MRSA by 3 logs or more on PPE materials within 1 minute at 6 inches from a UV-C lamp and within 3 minutes at 2 feet from the lamps. Reduction in MRSA was equivalent at different heights within the booth and was not significantly reduced by5% fetal calf serum. These data suggest that the UV-C disinfection booth could be useful for rapid disinfection of contaminated full-body coverage PPE used in care of patients with suspected or confirmed Ebola virus infection prior to removal. Our findings are consistent with a recent study that
demonstrated that a pulsed xenon UV room disinfection unit was effective in reducing recovery of a nonenveloped canine parvovirus on PPE by more than 4 logs with a 5-minute exposure time at a distance of 2 meters.7 The UV-C disinfec- tion booth described here offers some potential advantages over room disinfection units. The booth is quiet and the exposure time of 3 minutes is feasible for busy personnel. The use of a booth limits the site of UV-C exposure to a small area, avoiding potential exposure of other personnel, while positioning of lamps on all 4 corners of the booth provides 360° UV-C exposure. Our study has some limitations. First, although we
demonstrated that UV-C did not penetrate through PPE used in our facility, other hospitals considering use of UV-C should verify that it does not penetrate their PPE. In addition, testing of penetration of UV-C should include wet or heavily soiled PPE. Although UV-C did not penetrate the face shield tested in this study, to minimize the risk of ocular exposure, additional protection such as UV-C filtering goggles might be reasonable.
figure 1. The efficacy of an ultraviolet-C radiation disinfection booth for reduction of bacteriophage MS2 (A) and methicillin- resistant Staphylococcus aureus (MRSA) (B) with and (C) without organic load dried onto carriers including glove and gown material and steel disks. The log10 plaque-forming unit (PFU) and log10 colony-forming unit (CFU) reductions per square centimeter are shown for bacteriophage MS2 and MRSA, respectively. Carriers contained 5 to 6 log10 PFU or CFU of the organisms. The carriers were irradiated for 30 seconds or 1, 3, or 5 minutes at a distance of 6 inches from one of the ultraviolet-C lamps or in the center of the booth at 2 feet from each of the 4 ultraviolet-C lamps. The means of the data from experiments conducted in triplicate are presented. Error bars indicate standard error.
Second, although 5% fetal calf serum did not adversely affect the efficacy of disinfection, it is likely that efficacy would be reduced by heavy contaminationwith blood, stool, or vomitus.
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