Evaluation of a UVC Based Shoe Sole Decontamination Device to Reduce Pathogen Colonization on Floors, Surfaces and Patients

Tasnuva Rashid, Kelley Poblete, Jonathan Amadio, Irtiza Hasan, Khurshida Begum, M. Jahangir Alam and Kevin W. Garey. University of Houston College of Pharmacy, Houston, TX University of Texas, School of Public Health, Houston, TX University of Edinburgh, UK

Background: Few infection control resources are devoted to control transfer of potentually pathogenic organisms from shoe bottoms. Recently, a UVC decontamination device has become available that delivers germicidal UVC radiation to shoe bottoms. The objective of this study was to demonstrate that shoe soles can be vectors for healthcare associated infection and that a UVC shoe bottom decontamination device would be effective at decreasing this risk.

Methods: Three clinical bacterial strains Staphylococcus aureus (SA 168), Enterococcus faecalis, and Escherichia coli (ATCC 25922) , and a non-toxigenic strain of C. difficile (ATCC 700057) were spiked onto standardized rubber soled shoe bottoms and then randomly selected to UVC exposure or no UVC exposure. Experiments were performed to test the efficacy of the UVC device to decontaminate shoe sole bottoms, flooring, and colonization of a simulated healthcare environment and patient.

Results: The UVC device significantly decreased shoe sole contamination for all tested bacterial species (p<0.01 for each species). Shoe sole exposure to the UVC device significantly decreased floor contamination for all floor types and species tested (p<0.01 , for all experiments). Log10 reduction was the highest for E. coli (2.6±0.79) followed by E. faecalis (2.19±0.68), S. aureus (1.74±0.88), and C. difficile (0.42±0.54) (p<0.0001, all analyses). Exposure of shoe soles to the UVC device significantly decreased contamination (mean log10 reduction: 2.79±1.25; p<0.0001). Proportions of samples from furniture, bed, and patient samples decreased from 96-100% positive in controls compared to 5-8% in UVC device experiments (p<0.0001, for all analyses).

Conclusion: A UVC decontamination device was shown to reduce CFU counts of relevant pathogenic organism from shoe soles with subsequent decreased colonization of floors, healthcare equipment and furniture, beds, and a patient dummy.