Evaluation of a shoe sole UVC device to reduce pathogen colonization on floors, surfaces and patients

An ultraviolet C (UVC) decontamination device that delivers germicidal UVC radiation to the soles of shoes has become available recently.

To demonstrate that shoe soles can be vectors for healthcare-associated infection, and to investigate if a UVC shoe sole decontamination device would decrease this risk effectively.

Three bacterial strains (Staphylococcus aureus, Enterococcus faecalis and Escherichia coli) and a non-toxigenic strain of Clostridium difficile were spiked on to standardized rubber-soled shoe soles and then selected at random for UVC exposure or no UVC exposure. Experiments were performed to test the efficacy of the UVC device to decontaminate shoe soles and flooring. E. faecalis was spiked on to shoes to assess colonization of a simulated healthcare environment and patient.

The UVC device decreased shoe sole contamination significantly for all tested bacterial species, and decreased floor contamination significantly for all floor types and species tested (P<0.01 for all experiments). The log₁₀ reduction was the highest for E. coli (mean±standard deviation 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 for all analyses). Exposure of shoe soles to the UVC device decreased contamination significantly (mean log₁₀ reduction 2.79±1.25; P<0.0001). Proportions of samples from furniture, bed and patient dummy samples decreased from 96-100% positive in controls to 5-8% positive in UVC device experiments (P<0.0001 for all analyses).

A UVC decontamination device was shown to reduce the colony-forming unit counts of relevant pathogenic organisms from shoe soles with subsequent decreased colonization of floors, healthcare equipment, furniture, beds and a patient dummy.