Abstract
Aerial dispersion of pathogens is recognized as a potential transmission route for hospital acquired infections; however, little is known about the link between healthcare worker (HCW) contacts’ with contaminated surfaces, the transmission of infections and hospital room design. We combine computational fluid dynamics (CFD) simulations of bioaerosol deposition with a validated probabilistic HCW–surface contact model to estimate the relative quantity of pathogens accrued on hands during six types of care procedures in two room types. Results demonstrate that care type is most influential (P < 0.001), followed by the number of surface contacts (P < 0.001) and the distribution of surface pathogens (P = 0.05). Highest hand contamination was predicted during Personal care despite the highest levels of hand hygiene. Ventilation rates of 6 ac/h vs. 4 ac/h showed only minor reductions in predicted hand colonization. Pathogens accrued on hands decreased monotonically after patient care in single rooms due to the physical barrier of bioaerosol transmission between rooms and subsequent hand sanitation. Conversely, contamination was predicted to increase during contact with patients in four‐bed rooms due to spatial spread of pathogens. Location of the infectious patient with respect to ventilation played a key role in determining pathogen loadings (P = 0.05).
Highlights
Risk of healthcare-acquired infections (HCAI) is omnipresent in healthcare facilities worldwide, and understanding transmission routes is key to effective control
Evidence suggests that at least 20% of HCAIs potentially could have arisen from an environmental reservoir (Harbarth et al, 2003) and several recent studies have highlighted the importance of surface contamination and indicated a causal link to subsequent patient infection (Bhalla et al, 2004a)
A computational fluid dynamics (CFD) model incorporating a polydisperse particle release based on known particle size data from respiratory (Han et al, 2013; Xie, 2008) and environmental (Hathway et al, 2013) sources could enable an estimation of the resulting spatial contamination, which can be applied in pathogen accretion model (PAM)
Summary
Risk of healthcare-acquired infections (HCAI) is omnipresent in healthcare facilities worldwide, and understanding transmission routes is key to effective control. Major studies have highlighted that environmental contamination, through the deposition of bioaerosol on surfaces, cannot be underestimated in the contribution to fomite-based infection transmission (Dancer, 2008; King et al, 2013; Otter et al, 2011; Rusin et al, 2002) Surfaces such as bed rails have been linked with harboring microorganisms that cause hospital infections, and many frequently used surfaces in hospitals have been found to sustain viable pathogens including staphylococci, enterococci (Duckro et al, 2005; Hayden et al, 2008; Pittet et al, 2006), and Clostridium difficile (Roberts et al, 2008). Pathogens have been shown to accrue on HCW hands as they touch surfaces (Pittet et al, 1999), and there is evidence they can subsequently be transmitted to patients (Hayden et al, 2008)
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