Longitudinal Assessment of Contamination Patterns on Workstations on Wheels (WOWs)

Abstract

Background Representations of contamination on portable medical equipment inform strategies to prevent transmission and healthcare-associated infections (HAIs). While periodic disinfection of equipment is required in most hospitals, the complexity of demands on staff may limit their ability to adequately disinfect multiple surfaces and touch points on a piece of equipment. The purpose of this study was to determine if current disinfection practices were effectively managing bioburden on WOWs on our hospital wards. Methods Samples were collected using press plate for four weeks from 10 WOWs on three medical-surgical units in our hospital. The sampling scheme limited the ability of staff to anticipate sampling and ensured multiple surfaces on each WOW were consistently sampled. Aerobic bacterial colony counts were calculated after 24 hours of incubation. Bayesian multilevel models estimated the mean bioburden and compared bioburden from different locations on WOWs. Results Out of the 452 samples, the estimated mean colony count (95% credible interval) was 29.2 (16.1-51.1). The incident risk-ratio comparing the handle to the other surfaces on the WOWs were 0.43 (0.32-0.55) for the keyboard, 0.29 (0.22-0.38) for the tray, and 0.22 (0.16-0.29) for the mouse. Conclusions The handle used for moving the WOW around, had greater bioburden compared to the keyboard, tray, or the mouse. Difference in the bioburden may reflect number of touches and lack of hand hygiene when moving equipment. The lower bioburden on keyboards and mouses may conversely reflect greater attention to hand hygiene or may be an artifact of sampling (less contact with press plates). The correlation of bioburden to HAI transmission was not studied here so the significance of bioburden alone in the absence of HAI monitoring is uncertain. Representations of contamination on portable medical equipment inform strategies to prevent transmission and healthcare-associated infections (HAIs). While periodic disinfection of equipment is required in most hospitals, the complexity of demands on staff may limit their ability to adequately disinfect multiple surfaces and touch points on a piece of equipment. The purpose of this study was to determine if current disinfection practices were effectively managing bioburden on WOWs on our hospital wards. Samples were collected using press plate for four weeks from 10 WOWs on three medical-surgical units in our hospital. The sampling scheme limited the ability of staff to anticipate sampling and ensured multiple surfaces on each WOW were consistently sampled. Aerobic bacterial colony counts were calculated after 24 hours of incubation. Bayesian multilevel models estimated the mean bioburden and compared bioburden from different locations on WOWs. Out of the 452 samples, the estimated mean colony count (95% credible interval) was 29.2 (16.1-51.1). The incident risk-ratio comparing the handle to the other surfaces on the WOWs were 0.43 (0.32-0.55) for the keyboard, 0.29 (0.22-0.38) for the tray, and 0.22 (0.16-0.29) for the mouse. The handle used for moving the WOW around, had greater bioburden compared to the keyboard, tray, or the mouse. Difference in the bioburden may reflect number of touches and lack of hand hygiene when moving equipment. The lower bioburden on keyboards and mouses may conversely reflect greater attention to hand hygiene or may be an artifact of sampling (less contact with press plates). The correlation of bioburden to HAI transmission was not studied here so the significance of bioburden alone in the absence of HAI monitoring is uncertain.