Effect of Increased Cleaning on Keyboard Bioburden and Employee Absence in an Office Building


Insufficient cleaning can create reservoirs of microorganisms, resulting in the spread of infection in the workplace. In this study, we examined the effects of increased cleaning of high-frequency touch sites on bioburden and absence rates at an office building. Daily cleaning of computer keyboards, mice, and telephones was performed on one floor and compared with a control floor. Contact plate samples were taken weekly from keyboards and bacterial contamination was assessed over a 3-month period. Increased cleaning and bioburden were compared to employee absence rates. Increased cleaning reduced overall bioburden on keyboards from 27–44 CFU/25 cm2 to 7–11 CFU/25 cm2 (n = 550), when compared with standard practice. Keyboards were found, however, to be recontaminated once used. Levels of bacteria from control floors decreased over the intervention period. Skin flora was most commonly isolated. Isolation of Enterococcus spp., suggesting fecal contamination, was reduced after increased cleaning. Regular cleaning reduces bioburden and has a lasting effect. Despite efficacy of increased cleaning, there was no significant effect on absences due to the wide variability of absence rates over time.


Speaker / Author: 
Samuel Yui, MSc, Environmental Research Laboratory, University College London Hospitals
Shanom Ali, PhD, Environmental Research Laboratory, University College London Hospitals
Monika Muzslay, MSc, Environmental Research Laboratory, University College London Hospitals
Peter Wilson, MA, MD, FRCP, FRCPath, Department of Microbiology and Virology, University College London Hospitals
Month Year: 
June 2020
Page #: 
Publication Month: 
June 2020