Far-UV Light Disinfection of Hospital Computer Keyboards

Author's note: This article is based upon work supported in part with funds provided by the VA National Center for Patient Safety plus resources and the use of facilities at the VA Central California Health Care System.

Electronic equipment such as computer keyboards that is shared and touched frequently by hospital caregivers in patient-care areas have been shown to harbor a variety of bacterial and viral pathogens. These devices serve as significant vectors of transmission for such organisms. Computer users unconsciously touch their eyes, mouth and nose while typing, and are sometime neglect to wash their hands after providing patient care. Unfortunately, such equipment is difficult to clean and disinfect, due to the potential damage caused by water-based cleaning products and the difficulty and time spent in wiping and drying all exposed and irregular surfaces.

Ultraviolet (UV) radiation has been a known mutagen at the cellular level for more than a century. The lethal action of sunlight on certain bacteria (known as ultraviolet germicidal irradiation) was demonstrated as early as 1877. Studies in the 1940s and 1950s examined the effect of artificial UV light on specific species of bacteria in laboratory settings. Practical applications of this technology have focused mainly on purification of water and in air handling systems. A literature review shows that use of UV light disinfection of surfaces in healthcare settings has thus far been limited to clinical laboratory work surfaces and equipment.

Recent studies have shown that specific wavelengths and exposure times of ultraviolet light can effectively kill strains of bacteria in both laboratory cultures and animal tissue. At certain wavelengths, UV light will break the molecular bonds within micro-organismal DNA, thereby destroying them, rendering them harmless or prohibiting growth and reproduction. Investigators have also tested the effectiveness of traditional disinfectants commonly used in hospitals to clean computer keyboards. The most effective disinfectant was one in which the solution remains on the cleaned surface for at least ten minutes before it is wiped off. This potentially puts the keyboard unusable for ten minutes on a busy nursing unit, and the process of application and wiping or air-drying is time-consuming. In addition, from an environmental standpoint, the volatile organic chemicals emitted as gases from certain liquid disinfectant solutions may have short- and long-term adverse health effects when released into the environment, presenting a potential danger to both workers and patients. Clearly, alternative safe and efficient disinfection methods are desirable.