Ultraviolet (UV)-reflective paint with ultraviolet germicidal irradiation (UVGI) improves decontamination of nosocomial bacteria on hospital room surfaces

ABSTRACT

An ultraviolet germicidal irradiation (UVGI) generator (the TORCH, ClorDiSys Solutions, Inc.) was used to compare the disinfection of surface coupons (plastic from a bedrail, stainless steel, and chrome-plated light switch cover) in a hospital room with walls coated with ultraviolet (UV)-reflective paint (Lumacept) or standard paint. Each surface coupon was inoculated with methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant Enterococcus faecalis (VRE), placed at 6 different sites within a hospital room coated with UV-reflective paint or standard paint, and treated by 10 min UVC exposure (UVC dose of 0–688 mJ/cm² between sites with standard paint and 0–553 mJ/cm² with UV-reflective paint) in 8 total trials. Aggregated MRSA concentrations on plastic bedrail surface coupons were reduced on average by 3.0 log₁₀ (1.8 log₁₀ Geometric Standard Deviation [GSD]) with standard paint and 4.3 log₁₀ (1.3 log₁₀ GSD) with UV-reflective paint (p = 0.0005) with no significant reduction differences between paints on stainless steel and chrome. Average VRE concentrations were reduced by ≥4.9 log₁₀ (<1.2 log₁₀ GSD) on all surface types with UV-reflective paint and ≤4.1 log₁₀ (<1.7 log₁₀ GSD) with standard paint (p < 0.05). At 5 aggregated sites directly exposed to UVC light, MRSA concentrations on average were reduced by 5.2 log₁₀ (1.4 log₁₀ GSD) with standard paint and 5.1 log₁₀ (1.2 log₁₀ GSD) with UV-reflective paint (p = 0.017) and VRE by 4.4 log₁₀ (1.4 log₁₀ GSD) with standard paint and 5.3 log₁₀ (1.1 log₁₀ GSD) with UV-reflective paint (p < 0.0001). At one indirectly exposed site on the opposite side of the hospital bed from the UVGI generator, MRSA concentrations on average were reduced by 1.3 log₁₀ (1.7 log₁₀ GSD) with standard paint and 4.7 log₁₀ (1.3 log₁₀ GSD) with UV-reflective paint (p < 0.0001) and VRE by 1.2 log₁₀ (1.5 log₁₀ GSD) with standard paint and 4.6 log₁₀ (1.1 log₁₀ GSD) with UV-reflective paint (p < 0.0001). Coating hospital room walls with UV-reflective paint enhanced UVGI disinfection of nosocomial bacteria on various surfaces compared to standard paint, particularly at a surface placement site indirectly exposed to UVC light.

KEYWORDS:

• Environmental decontamination
• hospital room
• surfaces
• ultraviolet germicidal irradiation
• UV-reflective paint

Acknowledgments

The authors thank Nathan Harms for his laboratory support Kathleen Boulter, and Angela Vasa, and Michelle Schwedhelm for coordinating access to the Nebraska Biocontainment Unit.

Funding

This work was financially supported by the University of Nebraska Medical Center and Nebraska Biocontainment Unit. The TORCH is on loan to the research group from ClorDiSys Solutions, Inc. and the UVC Max paint was donated from Lumacept. However, neither ClorDiSys nor Lumacept were part of the research team, party to experimental design, or aware of the results of the study ahead of print. ClorDiSys has put no conditions on use of the TORCH except that the instrument be returned when the study is completed. Lumacept has put no conditions on use of UVC Max. No authors have any financial disclosures.