Mf King

Modeling environmental contamination in hospital single‐ and four‐bed rooms

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).

Relationship between healthcare worker surface contacts, care type and hand hygiene: an observational study in a single-bed hospital ward

This study quantifies the relationship between hand hygiene and the frequency with which healthcare workers (HCWs) touch surfaces in patient rooms. Surface contacts and hand hygiene were recorded in a single-bed UK hospital ward for six care types. Surface contacts often formed non-random patterns, but hygiene before or after patient contact depends significantly on care type (P=0.001). The likelihood of hygiene correlated with the number of surface contacts (95% confidence interval 1.1-5.8, P=0.002), but not with time spent in the room. This highlights that a potential subconscious need for hand hygiene may have developed in HCWs, which may support and help focus future hygiene education programmes.

Pilot-scale Biofiltration at a Materials Recovery Facility: The Impact on Bioaerosol Control

This study investigated the performance of four pilot-scale biofilters for the removal of bioaerosols from waste airstreams in a materials recovery facility (MRF) based in Leeds, UK. A six-stage Andersen sampler was used to measure the concentrations of four groups of bioaerosols (Aspergillus fumigatus, total fungi, total mesophilic bacteria and Gram negative bacteria) in the airstream before and after passing through the biofilters over a period of 11 months. The biofilters achieved average removal efficiency (RE) of 70% (35 to 97%) for A. fumigatus, 71% (35 to 94%) for total fungi, 68% (47 to 86%) for total mesophilic bacteria and 50% (-4 to 85%) for Gram negative bacteria, provided that the inlet concentration was high (103-105 cfu m-3), which is the case for most waste treatment facilities. The performance was highly variable at low inlet concentration with some cases showing an increase in outlet concentrations, suggesting that biofilters had the potential to be net emitters of bioaerosols. The gas phase residence time did not appear to have any statistically significant impact on bioaerosol removal efficiency. Particle size distribution varied between the inlet and outlet air, with the outlet having a greater proportion of smaller sized particles that represent a greater human health risk as they can penetrate deep into the respiratory system where gaseous exchange occurs. However, the outlet concentrations were low and would further be diluted by wind in full scale applications. In conclusion, this study shows that biofilters designed and operated for odour degradation can also achieve significant bioaerosol control in waste gas.

Isolating infectious patients: organisational, clinical and ethical issues

Background: Isolating infectious patients is essential to reduce infection risk. Effectiveness depends on identifying infectious patients, transferring them to suitable accommodations, and maintaining precautions. Methods: Online study to address identification of infectious patients, transfer, and challenges of maintaining isolation in hospitals in the United Kingdom. Results: Forty‐nine responses were obtained. Decision to isolate is made by infection prevention teams, clinicians, and managers. Respondents reported situations where isolation was impossible because of the patients physical condition or cognitive status. Very sick patients and those with dementia were not thought to tolerate isolation well. Patients were informed about the need for isolation by ward nurses, sometimes with explanations from infection prevention teams. Explanations were often poorly received and comprehended, resulting in complaints. Respondents were aware of ethical dilemmas associated with isolation that is undertaken in the interests of other health service users and society. Organizational failures could delay initaiting isolation. Records were kept of the demand for isolation and/or uptake, but quality was variable. Conclusion: Isolation has received the most attention in countries with under‐provision of accommodations. Our study characterizes reasons for delays in identifying patients and failures of isolation, which place others at risk and which apply to any organization regardless of availability. It also highlights the ethical dilemmas of enforcing isolation.

Novel technology for door handle design

We note the recent article on ‘The potential of alcohol release doorplates to reduce surface contamination during hand contact’ in the Journal of Hospital Infection [1]. We agree that reducing microbial contamination of frequently touched door surfaces and bacterial transfer via hands could feasibly reduce the risk of healthcare-associated infections (HCAIs) [1–3]. We recently examined a novel prototype door handle with precisely the same intention. This door handle is steel-framed and vertically aligned with the hand-grip portion encased by a specially prepared surface material (Figure 1).