Room Disinfection: which technology should I choose?
By Dr. Nicolas Hedin
In 1991 a study by Weinstein revealed that healthcare-associated infections (HAI) were 40 to 60% caused by patient’s endogenous flora, between 20 to 40% through the hands of hospital personnel and approximately 20% of the cases were due to environmental, food or air contamination. There is mounting evidence pointing towards the importance of ambient cleaning/disinfection to prevent and control HAI in hospitals. The common HAI-causing pathogens have the innate ability to survive on different surfaces inside the hospital for long periods of time. Among these organisms, the most common are: Clostridium difficile, meticillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), Acinetobacter spp. and norovirus.
Scientific evidence shows that contaminated surfaces contribute positively to the endemic transmission of most of these pathogens. Admission of a healthy patient to a room previously occupied by a VRE, MRSA or Clostridium difficile infected person increases the chances of HAI infection by at least a factor of two. There is also a study showing that improving room disinfection reduces the increased risk of HAI infection. Zimlichman et al. estimated in 2013 that 9.8 billion dollars per year are spent due to HAI infections. It is thus clear that proper environmental disinfection is a key point when discussing healthcare.
In 2011 Manian and collaborators demonstrated that rooms contaminated with multidrug-resistant Acinetobacter baumannii complex and MRSA were difficult to clean and even after four rounds of cleaning/disinfection with bleach, the pathogens remained in the room. The authors concluded that the suboptimal conditions of the cleaning/disinfection process per se are the causes of these results rather than the ineffectiveness of the disinfectant. Several other studies highlight the importance of the human factor. Finding the proper protocol seems mandatory, and educating personnel is also a key point, as this might help them understand the importance of their activity. It is also a fact that modifying human behavior is sometimes a difficult task: while the education process is active and ongoing, the results are positive but after some months they return to the starting point. In this sense, the development of “no-touch automated room disinfection” (NTD) technology helps achieve proper cleaning and disinfection standards.
No-Touch Automated Room Disinfection (NTD) Technologies
In recent years several NTD systems have been developed, with the most tested and useful ones relying on hydrogen peroxide (H2O2) or ultraviolet radiation (UV). Both technologies are in the spotlight, as they have been proposed as accepted methods for N95 mask decontamination according to CDC guidelines, given the context of COVID-19 where there is a shortage of N95 masks.
Aerosolized Hydrogen Peroxide (aHP)
aHP delivers H2O2 generated by pressure from a solution with a relatively low concentration (5–6%). Peroxide is delivered together with silver cations which help stabilize hydrogen peroxide and improve bactericidal efficacy. Different particle sizes can be generated, producing a ‘dry-mist hydrogen peroxide’ that decomposes naturally to oxygen and water. aHP is easy to use and relatively inexpensive, but depending on room size multiple units may be required. Sealing doors and air vents is mandatory, and the process can take 2 to 4 hours.
Vaporized Hydrogen Peroxide (vH2O2)
vH2O2 uses heat to vaporize a 30–35% hydrogen peroxide solution, achieving higher concentrations compared to aHP. Two approaches exist: HPV (hydrogen peroxide vapor) which condenses on surfaces, and VHP (vaporized hydrogen peroxide) which does not. Both are effective against resistant pathogens and spores. This option is often chosen during outbreaks. However, it requires sealing the room, monitoring peroxide levels, and cycles can last 2 to 8 hours.
Ultraviolet Radiation (UV)
UV radiation is divided into UVA, UVB, and UVC. UVC is the most lethal option for microorganisms as it disrupts DNA and RNA. UVC systems often move automatically around the room to ensure coverage. They have been proposed as reliable methods to decontaminate N95 respirators. UVC offers shorter disinfection times (10–45 minutes) and does not require sealing the room, but effectiveness depends on distance and light incidence. Pulsed Xenon UV (PX-UV) is another approach, though less studied.
Assessing NTD Effectiveness
No-touch automated room disinfection technology is a solution for healthcare facilities, sterile processing departments, and industry. However, proper assessment is crucial. Traditional microbiological approaches are impractical for routine analysis. Alternatives include biological indicators (e.g., fluorescence-based indicators for hydrogen peroxide) and tridimensional chemical indicators to ensure proper exposure. For UV, chemical indicators and dosimeters are used to verify correct UV-dose, including recently released 3D UV chemical indicators.
