The Role Of Surfaces In The Transmission Of Bioaerosols From Source To Patient In Hospital Rooms

INTRODUCTION: Aerial dispersion of bioaerosols and subsequent contamination of surfaces is recognised as a potential transmission route for health-care acquired infections. Pathogens accrue on health-care workers’ (HCW) hands as they touch surfaces and can subsequently be transmitted to other patients.

METHODS: Computational fluid dynamics (CFD) was used to predict bioaerosol deposition in a single and multi-bed hospital rooms. A Monte-Carlo model was developed using the CFD deposition patterns in conjunction with clinical observation of surface contact sequences to predict the contamination levels of bacteria on HCWs’ hands as they perform patient care in the two rooms.

RESULTS: Hand colonisation depends on care type, room layout and in particular on the spatial distribution of pathogens between surfaces, which is influenced by ventilation. During care within multi-bed rooms colonisation levels increase due to the spatial spread of microorganisms contaminating multiple patient surfaces caused by the ventilation strategy. Positioning infectious patients within an unobstructed path between the inlet and outlet diffuser significantly reduces cross contamination to other patients surfaces.

CONCLUSIONS: Colonisation levels of HCWs’ hands are likely to be significantly lower after care in single patient rooms than after care in a multi-bed ward and ventilation design is vitally important in curtailing bioaerosol spread.