Altapure vs. the Competition
The following is a brief description and analysis of four (4) competitive technologies:
WARNING: A recent peer reviewed study published in "Infection Control and Hospital Epidemiology" shows that 35% of C. difficile (C-Diff.) patient rooms still had viable and detectable residual spores, EVEN AFTER BOTH terminal cleaning by hand AND treatment by UV light, on high touch surfaces. (More Information Below)
Ultraviolet (UV) light disinfection technology has been around since the mid-20th century. It is in the area of the electromagnetic spectrum found between the short wavelength portions and the x-ray region, and it is not visible to the human eye. It kills microorganisms by damaging their DNA.
The effectiveness & reproducibility of germicidal UV is dependent upon:
- The reflective and light absorptive nature of all surfaces in the treated area.
- Absence of objects in the room / no shadowing.
- Distance from the light source.
- Length of time a micro-organism is exposed to UV light.
- Line of sight exposure of the micro-organisms to the UV light.
- Limited power fluctuations of the UV source that impact the EM wavelength.
- Absence of particles that can protect the micro-organisms from UV light (pre-clean room).
- Power / Luminance / Intensity of the UV light source.
- A micro-organism’s ability to withstand and survive UV light during its exposure.
- Clean bulbs & covers since dust or other films can coat the bulbs / covers, and lower or obscure UV light output.
- Location or placement of the UV unit in the room.
- Age of the bulb.
Disadvantages of germicidal UV light Technology:
- Location dependent for efficacy.
- Efficacy decreases as the distance from the light source increases.
- Accuracy and Reproducibility is not guaranteed as a human (not perfect) must move the machine around in the room.
- Peer reviewed study shows 35% of C. difficile (C-Diff.) patient rooms still had viable and detectable residual spores, even after both terminal cleaning by hand and treatment by UV light, on high touch surfaces.
- Unable to achieve “no growth” for C. difficile spore kill throughout room.
- Shadowing (non-line of site from UV light source) reduces efficacy and increases risk.
- Time dependent / D-Value related (time to get at least a 90% kill).
- Room surfaces absorb UV light energy (efficacy via room surface reflections is misleading).
- Will damage eye tissue if accidentally exposed.
- Air movement patterns can impact performance .
- Replacement bulbs can be very expensive.
- Bulb performance can be degraded by surface contamination like lint, dust, etc.
- Damage / Photo oxidation of room materials by UV light.
- Unable to efficaciously treat connected areas like bathrooms at the same time with a single device (especially problematic for C. difficile spores).
- Light output can degrade as light source ages.
- Penetration is "not" effective for porous surfaces such as sheets, curtains, and upholstery.
CAUTION: If you own, or intend to purchase a UV light system, be advised that any shadowed surfaces will not be treated (or at least treated enough to eliminate spores and other micro-organisms), and any untreated or inadequately treated surfaces are a real source of contamination that can jeopardize patient health and/or patient life. The published literature shows that UV cannot obtain a complete kill of common pathogens found in a medical facility.
Example: A research study published in the May, 2013 issue of "Infection Control And Hospital Epidemiology" states the following:
Quote: “In a real-world setting, we found that 35% of CDI (C. difficile infection) rooms had residual spores detectable by culture after standard terminal cleaning and operation of the devices (UV light devices).”
According to this research paper, it is also important to note that these positive C-Diff. spore cultures were even taken on “high-touch surfaces” that were both terminally cleaned by housekeeping staff and treated by UV light.
Source: Sitzlar et al., “An Environmental Disinfection Odyssey: Evaluation of Sequential Interventions to Improve Disinfection of Clostridium difficile Isolation Rooms”, Infection Control And Hospital Epidemiology, Vol. 34, No. 5, Special Topic Issue: The Role of the Environment in Infection Prevention (May 2013), pp. 459-465, 
Proponents of this technology claim that “reflected light” will flood the entire space even behind large objects. However, this claim has not been borne out by recent published studies showing the effects of shadowing. In accordance with the description of light offered by Stephen Hawkin a world-renowned physicist, light only travels in a straight line, it cannot be bent around corners. Outside of a straight-line exposure, shadowing by objects such as furniture and equipment, will prevent a full kill of the micro-organisms.
The differing ability of materials found in hospital room construction to reflect UV light, as well as shadowing, contributes to the inability to achieve at least a 6-log kill on all surfaces as compared with other platforms.
UV light technology can barely achieve a mean reduction value of only 3 log for C. difficile spores inside treated patient rooms. Log reductions less than 3 log, have also been found in the same treated spaces. [1, 3, 4]
The remaining pathogens can obviously be a direct source for infectious disease.
Recent studies show that its greatest kill range only occurs within feet of the UV light source, and its efficacy is dramatically reduced at 10 ft. Furthermore, UV light is not effective in penetrating porous surfaces such as sheets, curtains, and upholstery.
UV light products also do not disclose their D-value, which is a standard for biological evaluations. Why is this? We encourage you to review and compare the Log Reduction for this technology at 6 and 10 feet or more from the light source, especially behind shadowed surfaces, or around corners.
The long-term effects of intense UV light on materials found in a hospital setting have not been studied and/or published. UV light can degrade materials, especially plastics and rubber, over time through photo oxidation.
Three (3) Studies & UV Light – What The Results Really Mean:
Below is the analysis of three (3) studies and related data regarding UV light disinfection:
UV Study & Data # 1
Source: Nerandzic et al. BMC Infectious Diseases 2010, 10:197
Title: “Evaluation of an automated ultraviolet radiation device for decontamination of Clostridium difficile and other healthcare-associated pathogens in hospital rooms”
Author: Michelle M Nerandzic, Jennifer L Cadnum, Michael J Pultz, and Curtis J Donskey.
Quote: “On inoculated surfaces, application of Tru-D at a reflected dose of 22,000 μWs/cm^2 for ~45 minutes consistently reduced recovery of C. difficile spores and MRSA by >2-3 log10 colony forming units (CFU)/cm^2 and of VRE by >3-4 log10 CFU/cm^2. Similar killing of MRSA and VRE was achieved in ~20 minutes at a reflected dose of 12,000 μWs/cm^2, but killing of C. difficile spores was reduced. Disinfection of hospital rooms with Tru-D reduced the frequency of positive MRSA and VRE cultures by 93% and of C. difficile cultures by 80%.” (Abstract, pg. 1)
* Altapure Comment: You will notice that the UV light did NOT obtain a total kill of ANY biological challenge. In addition, the C. difficile spores were only reduced by 80%! Furthermore, this low log reduction that was obtained still required at least 45 minutes of direct light.
According to “Figure 2” in this study (shown above), the mean reduction values (log10 colony forming units (CFU)/cm^2 ) were given for MRSA, VRE, and C. difficile spores. The mean log reduction values for MRSA were all under 3.5 log reduction. The mean log reduction values for VRE were all under 4.5 log reduction. Finally, the mean reduction values for C. difficile spores barely passed 3 log reduction.
The Only Conclusion: All of the data sets show terrible log reduction performance. The use of UV light disinfection is like depending on a fire department that is incapable of putting out an entire fire.
UV Study & Data # 2
Source: Infection Control and Hospital Epidemiology, October 2010, vol. 31, no. 10
Title: “Room Decontamination with UV Radiation”
Author: William A. Rutala, PhD, MPH; Maria F. Gergen, MT (ASCP); David J. Weber, MD, MPH
Note: Distance from the light source is not specified.
Quote 1: “In our test room, the effectiveness of UV-C radiation in reducing the counts of vegetative bacteria on surfaces was more than 99.9% in approximately 15 minutes, and the reduction in C. difficile spores was 99.8% within 50 minutes. (pg. 4)
Quote 2: “UV-C radiation was more effective when there was a direct line of sight to the contaminant (MRSA, P = .06; VRE, P = .003; A. baumannii, P = .07; C. difficile, P < .001), but meaningful reduction (mean reduction, 3.3–3.9 log10) did occur when the contaminant was not directly exposed to the UV-C.” (pg. 4)
Quote 3: “However, because the presence of dirt and debris can decrease the effectiveness of UV-C disinfection, rooms should be cleaned before UV-C treatment." (pg. 5)
* Altapure Comment: UV light did NOT obtain a total kill of ANY biological challenge presented. In addition, it took 50 minutes just to obtain these poor results.
According to “Table 1” in this study (shown above), the mean reduction values (log10 colony forming units (CFU)/cm^2 ) were given for MRSA, VRE, and C. difficile spores. The mean reduction values for MRSA in DIRECT LIGHT was 4.31 log reduction, and 3.85 in INDIRECT LIGHT. The mean log reduction values for for VRE in DIRECT LIGHT was 3.90 log reduction, and 3.25 in INDIRECT LIGHT. Finally, the mean reduction values for C. difficile spores in DIRECT LIGHT was 4.04 log reduction, and 2.43 in INDIRECT LIGHT.
The Only Conclusion: Again, the use of UV light disinfection is like depending on a fire department that is incapable of putting out an entire fire. The data sets show terrible log reduction performance.
II. Hydrogen Peroxide Vapor
VHP (vaporized hydrogen peroxide). In order to achieve an acceptable 6-log reduction of a bacterial colony, a 30–35% concentration of hydrogen peroxide is required. While a consistent complete kill can be obtained, it requires more than three (3) hours to treat a standard patient room and obtain a 6-log kill of C. difficile, the most difficult of hospital pathogens to eradicate.
Disadvantages of vaporized hydrogen peroxide (VHP)
- Corrosive (uses at least 30-35% hydrogen peroxide).
- Long time to achieve efficacy (2.5-3) hours start to finish).
- Dangerous vapor - accidental exposure to vapor could cause worker injury.
- Fire hazard - all cellulose materials must be removed from room. **
- Room must be well sealed due to vapor.
- Air handler shut off.
- Catalytic converter failure would deny quick room access.
- Room materials could be jeopardized if catalytic converter failed.
* Note: Cellulose materials, such as toilet paper or note paper, must be removed from the room prior to treatment or spontaneous combustion / fire may occur.
Hydrogen peroxide at the 30-35% concentration is highly corrosive and must be removed following its deployment by a catalytic converter. A failure in their hydrogen peroxide converter at the end of the treatment process, would leave a high concentration of the corrosive liquid on all surfaces. Accidental inhalation of the vapors could also be harmful.
This technology option is also agent-dependent because the heat needed to create a vapor will destroy most other chemical agents.
(Source Material: Medical Design Magazine)
III. Compressed Air Nozzle Technology
This platform utilizes air pressure and a nozzle / jet apparatus to create and propel a liquid droplet into the treated space. Droplets produced in this fashion fall within a range of 7–30 µm and greater. All droplets are affected by the force of gravity. This technology is plagued by its “large” droplets and its lower density aerosol output.
The larger the droplet, the greater the gravitational force affecting its ability to stay aloft and reach far away surfaces. Brownian movement is also reduced, lowering the ability of the mist or aerosol to effectively treat complex surface geometries, adjacent rooms, and long vertical and horizontal runs. The corollary is also true: the smaller the droplet, the longer it will stay aloft and reach faraway surfaces. Larger droplets are also wet and can tend to puddle on horizontal surfaces.
Disadvantages of compressed air / nozzle / misting systems:
- Unable to achieve “no growth” for C. difficile spore kill throughout room, especially for connected spaces or rooms.
- Large droplet sizes.
- Short aerosol suspension time (due to large droplets).
- Reduced aerosol flow / penetration / Brownian movement (aerosol size dependent).
- Reduced ability to treat complex surface geometries and long vertical & horizontal runs.
- Small aerosol plume volume & plume density
- Compressed air source needed
- Application process can be loud
- Aerosol nozzles / jets can clog endangering success
- Longer application times
In a published physics text by William C. Hind, droplet sizes are compared to show, for example, a 1-µm droplet is 2,129.89% better at staying aloft than a 5-µm droplet, and a 1-µm droplet is 8,693.1% better at defeating the effects of gravity than a 10-µm droplet.
Because of the large droplet size, this technology is limited by the distance the droplets may travel, the ability to reach full efficacy in adjacent rooms, and the surface wetness that can be created.
One such system uses a mixture of hydrogen peroxide and silver. However, the presence of the silver ion residue prevents its use in pharmaceutical cleanrooms and most food applications as silver is considered by the Environmental Protection Agency (EPA) to be a heavy metal.
The D-value for spores - the time it takes to kill 90% of the most difficult organism for that particular technology platform, is unpublished for all of these technologies.
(Source Material: Medical Design Magazine)
IV. “Electrical Arc” Compressed Air Nozzle Systems:
One example of a modified compressed air system involves using a compressed air nozzle system that passes the liquid solution consisting of at least 7.5% Hydrogen Peroxide through an electrical arc which is claimed to create a "cold plasma ionized gas". This technology suffers from various problems. One of many problems is aerosol droplet size as discussed above.
Another problem is that due to the physio-chemical structure of their charged droplets, the hydroxyls remain uncombined with atmospheric products for ONLY as long as ten (10) seconds, which is a severe handicap for achieving the needed enhanced effect or efficacy for airborne or surface-attached pathogens that are more than ten (10) seconds away, due to long travel distances, complex geometries, or even areas that might have complex airflow patterns.
An even more pressing problem with this technology is that the aerosol droplets are “charged”. This is not desirable since if the charge is "the same" between the aerosol and the targeted surface(s), the aerosol may be repelled from, and not have contact with, the targeted surfaces. This outcome is especially problematic in places where life and health is at risk and surface disinfection / decontamination is expected or needed.
Literature Quote: "The plasma is tuned to a specific bonding frequency of active ingredients and creates a high concentration of reactive oxygen species (ROS) such as negatively charged hydroxyl ions. The negatively charged ions aggressively seek out positively charged areas to attach themselves, allowing for a thorough covering of all surfaces within the treatment area."
* Please click here for citations and references.