Enhanced Effect of Patient Room Disinfection Against Carbapenem-Resistant Enterobacter cloacae and Methicillin-Resistant Staphylococcus aureus Using UV-C Irradiation in Conjunction with UV-C Containment Unit

<b>Background/Objectives</b>: In environments with high-frequency contact surfaces, drug-resistant bacteria, such as carbapenem-resistant <i>Enterobacterales</i> and methicillin-resistant <i>Staphylococcus aureus</i> (MRSA), can survive for extended periods, contributing to healthcare-associated infections. Ultraviolet (UV)-C irradiation often fails to adequately disinfect shadowed areas, leading to a persistent contamination risk. We evaluated the effectiveness of using a UV-C containment unit (UVCCU) in conjunction with UV-C irradiation to improve the sterilization effects on both direct and indirect surfaces, including shadowed areas, and to assess the leakage of UV radiation to the surroundings. <b>Methods</b>: In a model patient room, agar media inoculated with carbapenem-resistant <i>Enterobacter cloacae</i> and MRSA were placed at multiple locations on direct and indirect surfaces around the bed. We used the UV-C irradiation system, UVDI-360, to irradiate the bedroom-environment surfaces with and without a UVCCU. The reduction in bacterial colony counts with and without the UVCCU was measured by counting colony-forming units and calculating the log reduction values, and the UV radiation leakage outside the UVCCU was measured. <b>Results</b>: The use of the UVCCU led to a significant reduction in MRSA colony counts, even in shadowed areas that had previously been inadequately disinfected (with the UVCCU: 2.7 [2.7-2.8]; without the UVCCU: 0.6 [0.5-0.7]; <i>p</i> < 0.01). Additionally, the use of the UVCCU kept the UV radiation leakage to the surrounding environment within regulated limits. <b>Conclusions</b>: These findings suggest that a UVCCU can enhance the disinfection efficacy for multidrug-resistant organisms on healthcare environmental surfaces. The portability and ease of use of the UVCCU indicate its promise as an auxiliary device for UV-C disinfection in healthcare settings.