Evaluation of an ultraviolet C light-emitting device for disinfection of electronic devices.

BACKGROUND: A tabletop-type ultraviolet C (UVC) light-emitting disinfecting device was evaluated for microbiologic effectiveness, safety, usability, and end-user satisfaction.

METHODS: Three different inoculums of methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, and Acinetobacter calcoaceticus-baumannii complex strains suspended in both saline and trypticase soy broth were applied onto stainless steel carriers and electronic device surfaces in triplicate and cultured for growth after UVC disinfection. Assessments of functionality and usability were performed by biomedical and human factors engineers. End-user feedback was captured using a standardized in-use survey.

RESULTS: The 54 stainless steel carriers displayed growth at inoculums as low as 102 colony forming units (CFU) when a quartz dish supplied by the manufacturer was used during UVC exposure. Without the quartz dish, 54 electronic device surfaces displayed no growth for inoculums from 102 -104  CFU for all organisms suspended in saline, but lower kill rates (95.7%-100%) for organisms in broth. Several minor safety and usability issues were identified prior to clinical evaluation. In-use evaluation revealed keen user endorsement; however, suboptimal sensitivity of the machine's input sensors during sequential object insertion precluded implementation.

CONCLUSIONS: Optimization of some safety and functionality parameters would improve a conceptually popular and microbiologically effective tabletop UVC disinfecting device.