News Author: Laurie Barclay, MD

April 28, 2006 — Disinfecting computer keyboards is effective and should typically be done daily, according to the results of a study reported in the April issue of Infection Control and Hospital Epidemiology. However, the investigators suggest that this would not be necessary if handwashing guidelines were followed.

"Computers are ubiquitous in the healthcare setting and have been shown to be contaminated with potentially pathogenic microorganisms," write William A. Rutala, PhD, MPH, from the University of North Carolina Health Care System in Chapel Hill, and colleagues. "The risk of transmission of pathogens from computer keyboards to patients would be prevented by compliance with current hand hygiene guidelines.... This study was performed to determine the degree of microbial contamination, the efficacy of different disinfectants, and the cosmetic and functional effects of the disinfectants on the computer keyboards."

The investigators evaluated the efficacy of 6 different disinfectants (1 each containing chlorine, alcohol, or phenol and 3 containing quaternary ammonium) against 3 test organisms (oxacillin-resistant Staphylococcus aureus [ORSA], Pseudomonas aeruginosa, and vancomycin-resistant Enterococcus species) inoculated onto study computer keyboards. They also determined functional and cosmetic damage to the computer keyboards after disinfectant use.

More than half of the keyboards harbored coagulase-negative staphylococci (100% of keyboards), diphtheroids (80%), Micrococcus species (72%), and Bacillus species (64%). Other pathogens cultured were ORSA (4% of keyboards), oxacillin-susceptible S. aureus (4%), vancomycin-susceptible Enterococcus species (12%), and nonfermentative Gram-negative rods (36%).

All disinfectants and even the sterile water control were effective at removing or inactivating more than 95% of the test bacteria, without functional or cosmetic damage to the keyboards after 300 disinfection cycles.

"Our data suggest that microbial contamination of keyboards is prevalent and that keyboards may be successfully decontaminated with disinfectants," the authors write. "Keyboards should be disinfected daily or when visibly soiled or if they become contaminated with blood.... We agree with other investigators who have recommended that routine disinfection be performed on computer keyboards that are used in patient care areas."

The North Carolina Statewide Program for Infection Control and Epidemiology and the University of North Carolina Health Care System supported this study. Two of the authors have disclosed various financial relationships with Clorox and/or Metrex.