In the previous two posts , my colleagues have discussed the choice of disinfectants for manual cleaning and effectiveness (or ineffectiveness) of manual cleaning.
In this post, I would like to discuss the range of technologies available to assist with patient room cleaning & disinfection. These technologies are typically referred to as “Touch-less” or “No-touch” disinfecting technologies. They are a valuable addition to a manual cleaning regime which is an essential component of infection prevention and are often complementary to one another. In this post we will review the breadth of technologies that are available to assist in patient room disinfection alongside manual disinfection.
To err is Human: As a summary from previous post, manual cleaning is sub-optimal for a variety of reasons. Very often, the use of disinfectants is inconsistent with the directions provided on the labels (less than ideal contact times, improper & inconsistent dilution etc.).
Fact: Did you know, for most surface disinfectants, EPA recommends 10 minute contact time to achieve complete disinfection?
Other factors including lack of proper training for cleaning personnel, retraining needed due to personnel turnover, confusion over whose job it is to clean also contribute to the issue .
To minimize the impact of less than optimal manual cleaning on patient health and safety, several technologies have become available to supplement overall disinfection & cleaning practices.
These technologies & systems  are broadly based on:
- Ultraviolet (UV) light & Violet light:
- Vaporization or Aerosolization of disinfectants
- Self-cleaning surfaces (impregnated/coated with microbicides or photosensitizers such as TiO2)
Technologies based on UV or near-UV light:
On the electromagnetic spectrum, the wavelengths from 100 nm to 400nm constitutes UV radiation. UV-radiation is further classified into UV-A (315-400nm), UV-B (280-315nm) and UV-C (100-280nm) radiations based on the wavelengths. Ultraviolet light, especially in the range of UV-C, is known to cause germicidal action due to its high frequency and associated high energy and has been used extensively in sterilization.
Xenex® (https://www.xenex.com/)  has developed a mobile automated system that generates pulses of intense UV-C light using Xenon, between wavelength spectrum of 200-320nm, to disinfect the patient rooms. There are other similar technologies, such as Tru-D® (http://tru-d.com/) , that are based on UV-C generation by mercury lamps. These systems are automated and are operated remotely. One of the challenges with these systems is that the UV-C radiation is harmful to human beings and are not recommended to operate while patients and healthcare workers still occupy the room. Generally, these systems are employed for one-time disinfection after patient is discharged and room is terminally cleaned.
But some systems, such as Indigo-clean® (http://www.indigo-clean.com/) , generate “High Intensity Narrow Spectrum” (HINS) light at the wavelength of 405nm which is non-harmful to humans. This HINS light can be generated & delivered through light fixtures. Thus it can be used in the background on a continuous basis to reduce microbial contamination actively.
All these systems based on light are very effective in killing microorganisms on surface that are directly in the line of sight.
Vaporization or Aerosolization of disinfectants:
Another interesting way to apply disinfectants effectively and consistently is to apply them as vapors or aerosols. There are a variety of manufacturers of these equipment that converts different liquid disinfectant into fine mists for disinfection purposes. Hydrogen peroxide is a popular choice among available disinfectants as it does not leave any residue (except for water) nor does it smell and its very effective against microbes but at the same time deemed non-toxic to humans.
Altrapure’s AP-4TM employs ultrasonic technology to generate sub-micron droplets of hydrogen peroxide for disinfection while Halomist® uses hydrogen peroxide in combination with silver. E-mist electrolyzes water and sprays it as micron-sized droplets onto the surfaces in the area and claims better liquid adhesion to the surfaces due to electrostatic nature of liquid droplets. Another technology, Zimek’s Micro-mist®, uses chlorine dioxide in combination with quaternary ammonium compounds (aka QUATS) as disinfectant [6-9].
Other disinfectants and combinations can replace the above mentioned disinfectants. For example, peracetic acid with hydrogen peroxide was evaluated alongside sodium hypochlorite [10, 11]. In-situ generation of ozone in a portable equipment to disinfect the patient rooms have been demonstrated .
Similar to UV-C based technology, these aerosol/mist systems are employed for one-time disinfection after patient is discharged and room is terminally cleaned. But a hydrogen peroxide based system that generates low concentrations of the active ingredient as mist is used continuously in the background .
These systems based on Aerosolization of disinfectants are very effective in killing microorganisms on surfaces that are not in direct line of sight.
Surfaces can be coated or impregnated with microbicides to impart antimicrobial activity. Copper Development Association (CDA) have developed Copper and Copper alloy surfaces and registered with EPA for public health claims for the antibacterial activity (99.9% reduction against different bacteria).
We, at Cupron in partnership with EOS, have developed polymeric surfaces with copper oxide as active ingredient that enjoy the same EPA public health claims. CDA surfaces and Cupron-EOS surfaces fall under hard surface category.
Self-cleaning surfaces can come as soft-surfaces as well and include patient gowns, bed linens and privacy curtains that have antimicrobial activity. Copper has shown to be an effective tool in microbial reduction on surfaces  and Silver based privacy curtains have shown to reduce microbial contamination .
One of the advantages for these self-cleaning surfaces, either soft surfaces or hard surfaces, is that they work in the back ground without much interruption to the work-flow in the health care settings.
Classification of Touch-less technologies:
Early in the post, I have categorized different technologies based on the mode of operation or method of application but it is very tempting to classify these no-touch technologies as “Active vs Passive” or “Continuous vs. Episodic”.
This is relevant because studies have shown that within hours of disinfection, the microorganisms are back on the surfaces . The UV-C based technologies and the aerosolization of disinfectants fall under Episodic & active category while HINS and Self-cleaning surfaces would fall under the Continuous & passive category.
There are certainly advantages and disadvantages associated with each system and perhaps a combination of these would provide the best care for the patients & healthcare professionals.
In the upcoming blogs, we will touch on effectiveness of these different technologies and review the clinical trial literature available on these technologies on the impact of Hospital acquired infections (HAIs). Stay tuned.
Feel free to add your thoughts ,experiences or comments as always in the box below!
- Cleaning Up: How Hospital Outsourcing Is Hurting Workers and Endangering patients, Dan Zuberi (ISBN: 978-0-8014-6981-7)
- Boyce JM, Modern technologies for improving cleaning and disinfection of environmental surfaces in hospitals, Antimicrobial resistance infection control, 2016; 5: 10
- http://www.zimek.com/zimek-technology.asp and http://www.zimek.com/pdf2/20140130-Zimek-EPA-Approved-82972-1.pdf
- Carling PC, Perkins J, Ferguson J, Thomasser A. Evaluating a new paradigm for comparing surface disinfection in clinical practice. Infect Control Hosp Epidemiol. 2014;35:1349–55
- Deshpande A, Mana TS, Cadnum JL, Jencson AC, Sitzlar B, Fertelli D, et al. Evaluation of a sporicidal peracetic acid/hydrogen peroxide-based daily disinfectant cleaner. Infect Control Hosp Epidemiol. 2014;35:1414–6
- Schmidt MG, Attaway Iii HH, Fairey SE, Steed LL, Michels HT, Salgado CD. Copper continuously limits the concentration of bacteria resident on bed rails within the intensive care unit. Infect Control Hosp Epidemiol. 2013;34:530–3
- Kotsanas D, Wijesooriya WR, Sloane T, Stuart RL, Gillespie EE. The silver lining of disposable sporicidal privacy curtains in an intensive care unit. Am J Infect Control. 2014;42:366–70
- Attaway, Hubert H. et al., Intrinsic bacterial burden associated with intensive care unit hospital beds: Effects of disinfection on population recovery and mitigation of potential infection risk, American Journal of Infection Control, Volume 40, Issue 10, 907 – 912