UNC Health Talk

Computer keyboards in health-care settings should be disinfected daily, UNC Health Care study concludes

In the health-care setting, computers are now almost as common as tongue depressors.

Within the University of North Carolina Health Care System, for example, nearly every room in which patients receive medical treatment, including operating rooms, is equipped with a computer. Doctors, nurses and other health-care providers use these computers routinely for a wide variety of purposes while seeing patients, such as viewing a patient’s test results or X-ray images and ordering laboratory tests.

“Using computers in this manner provides many advantages,” said Dr. William A. Rutala, UNC Health Care’s director of Hospital Epidemiology and a professor in the UNC School of Medicine. “However, it also can pose the risk of transmitting illness-causing bacteria from the computer keyboard to patients via the hands of their health-care providers.”

A new study conducted by Rutala and other UNC Health Care infection control specialists set out to determine the prevalence of bacterial contamination of computer keyboards at UNC Hospitals and tested the effectiveness of several commonly available disinfectant wipes used to clean the keyboards. The study is published in the April issue of the journal Infection Control and Hospital Epidemiology.

First, the researchers took samples from 25 computer keyboards at various locations inside UNC Hospitals and tested the samples for bacterial contamination. They found that each keyboard was contaminated with at least two types of bacteria. In particular, every keyboard tested positive for coagulase-negative staphylococci or CoNS, which is a major cause of bloodstream infections in hospitalized patients. In addition, 13 other types of bacteria were found, with the most common, after CoNS, being diphtheroids (found on 20 computers, or 80 percent), Micrococcus species (72 percent) and Bacillus species (64 percent).

They found that all seven wipes removed and/or inactivated at least 95 to 100 percent of the bacteria.

Next, the researchers intentionally contaminated seven laptop computer keyboards with three types of bacteria and then tested the effectiveness of seven different types of wipes used to clean the keyboards. They found that all seven wipes removed and/or inactivated at least 95 to 100 percent of the bacteria. The wipes tested included isopropyl alcohol wipes, CaviWipes, chlorine wipes, Clorox Disinfecting Wipes, Sani-Cloth Plus, Vesphene II SE wipes and paper towels moistened with sterile water.

In a second round of testing, the researchers recontaminated individual computer keys with Enterococcus species bacteria 6, 24 and 48 hours after the keyboard had been disinfected, to measure the sustained effectiveness of five types of wipes. In this test both alcohol and sterile water wipes performed very poorly, while CaviWipes, Clorox Disinfecting Wipes and Sani-Cloth Plus wipes were all 100 percent effective in eliminating Enterococcus bacteria up to 48 hours later. None of the wipes damaged the appearance of the keyboards or caused their letters to fade, and all of the computers worked without any functional problems.

Rutala and colleagues concluded that computer keyboards used in patient care areas should be routinely disinfected every day and when visibly soiled. In addition, if a keyboard cover is used, the cover should be disinfected as well, and mobile computers used by different patients should be disinfected between patient uses.

While this study did not test computer keyboards used outside the health-care setting, Rutala said it might be a good idea for anyone who shares a computer with other people to clean the keyboard with disinfectant wipes before use by a different person. “This might help prevent the spread of infection during cold and flu season,” Rutala said.

Rutala was lead author of the study. His co-authors were Matthew S. White, a second-year medical student at Wake Forest University School of Medicine; Maria F. Gergen, a medical technologist at UNC Hospitals; and Dr. David J. Weber, medical director of Hospital Epidemiology for the UNC Health Care System. Weber is also a professor in the UNC schools of Medicine and Public Health.

The UNC Health Care System is a not-for-profit integrated health care system owned by the state of North Carolina and based in Chapel Hill. It exists to further the teaching mission of the University of North Carolina and to provide state-of-the-art patient care. UNC Health Care is comprised of UNC Hospitals, ranked consistently among the best medical centers in the country; the UNC School of Medicine, a nationally eminent research institution; community practices; home health and hospice services in seven central North Carolina counties; and Rex Healthcare and its provider network in Wake County.