What levels of evidence need to be considered when reviewing a touchless disinfection system?

In the last post my colleague Dr Vikram Kanmukhla reviewed in detail the options for touchless disinfection systems as add on to manual cleaning and disinfection processes. In that post he reviewed the variety and depth of technologies. One of the overarching comments to that post is that all of these technologies are additional measures that can be added to current best practices-not only are they complementary to current practices but also other.

From this post one may have been wondering what levels of evidence or data is there to support these products use and how to look at the data available to decide upon the best options for your institution or facility? In this post I hope to clarify an evidence hierarchy with specific examples based upon a proposed model by McDonald and Arduino (1). It is important to note that these levels of data are not exclusive-a product does not have to fall into all of these categories to be considered to assist manual cleaning.

Evidentiary hierarchy In brief they presented a hierarchy of evidentiary data to demonstrate the clinical impact of both old and new environmental disinfection methodologies ranging from laboratory data at the lowest level to demonstration of reduced infections with consideration of sample size, baseline rates of infections and control of a number of factors including hand hygiene, infection control measures and antibiotic use being the highest level of evidence available.

At the lowest level Tier 1 data developed from laboratory testing that can show a 99.9% to 99.999% reduction in organisms has been suggested. This level of evidence is used to support EPA registered disinfectants (full approved list here), and sanitizers such as Cupron Enhanced EOS Solid Surface or copper alloys.

Numerous other products are outside of the EPA registration process and therefore using a well-controlled laboratory study of the highest rigor (Good Laboratory Practice (GLP)) with an internationally recognized or widely accepted standard developed by a technical body (AATCC, ASTM) is the lowest level of data acceptance. Alternately protocols developed by regulatory bodies can also be substituted as in the EPA protocols that were developed for continuously active sanitizing surfaces such as both the Cupron Enhanced EOS Surface which I along with my colleagues published available here(2), and copper alloys of 65% or higher who published their efficacy using the same protocols available here (3).

The next tier of data or Tier II evidence is data that demonstrates real world in use reductions of bioburden. This data is important as it provides real world use and variations on the efficacy data presented from the laboratory. Specific examples of bioburden reduction for copper based antimicrobial technologies include Schmidt et al (4) who conducted bioburden reduction studies on a range of copper alloy solid surface products, and Lazary et al (5) who reviewed the bioburden associated with copper hospital linens post use. For UV light and hydrogen peroxide vapor (HPV) fogging technology such as hydrogen peroxide vapor machines bioburden reduction a wide range of studies have been conducted. These include inoculating touch surfaces and placing them in a hospital room followed by irradiating them with UV (6-8), as well as assessing actual multi drug resistant organism (MDRO) bioburden reduction for both HPV and UV light systems (6-8).

Tier III data focuses the microbial reduction data from the laboratory or the real world hospital setting into clinical relevance. This relevance is determined to be either in hand contamination as a vector for infection transmission (something covered earlier in this blog series), or for same room transmission (another topic covered earlier in this blog series ). In both of these measures the metrics used are both surrogates for the environment-hand contamination from the environment and potentially environmentally influenced infections -so called “same room” infections. An example of this type of study is that of Passaretti et al (9) who found that HPV decontamination of MDRO patient rooms led to a 45% reduction in environmental contamination and an 80% reduction in acquisition of VRE among patients with a history of a prior MDRO-colonized room occupant (9).

Tier IV data extends the clinical relevance to documented reductions in discharge surveillance cultures as well as reduced pathogen transmission leading to clinical incidence. Examples of these studies include Datta et al (10), Simmons et al (11), and Mitchell et al (12). In the Datta (10) study 10 ICUs introduced a new cleaning regimen for rooms previously occupied by patients colonized with MRSA or VRE. Environmental monitoring showed decreased contamination of room surfaces as well as a drop in patient acquisition of MRSA. Simmons et al (11) introduced a PX-UV touchless disinfection method alongside a topical clearance protocol for MRSA colonized patients, and demonstrated a reduction in the rate of hospital acquired MRSA infections. A similar study utilizing HPV was reported by Mitchell et al who used environmental screening of patient rooms cleaning alongside surveillance of patient acquisition of MRSA throughout their facility. In line with an environmental drop in the proportion of rooms demonstrating MRSA contamination of 3.5% was also a reduction in MRSA acquisition from 9.0 to 5.3 per 10,000 patient days (12)

Tier V studies using controlled methodologies and a study design with a sample size and baseline rate to address the impact of environmental methods. Weber et al (13) produced an excellent review of the trails for UV and HPV systems in their article (available here) and table below taken from their publication. Capture2 Further examples include Sifri et al who published (14) that the use of Cupron Medical Textiles and Cupron Enhanced EOS Solid Surface is demonstrated to reduce MDRO and CDI in a unique trial of both soft and hard surfaces. Additional trials include Salgado et al (15) who assessed the impact of 6 copper alloy products in the ICU. One thing to note is that the majority of these studies are before-after or quasi experimental studies due to the nature of the interventions, and also the deployment of these technologies not interfering with hospital operations. Rigorous trial designs such as double blind cross over trials are rare but one recently published article by Marcus et al using copper oxide impregnated linens has such a rigor (16).

Randomized controlled studies such as the recently completed BETR study are rare and the study of Anderson et al (17) is worth highlighting due to the rigor of the trial and the endpoints.

If you are contemplating one or more of these technologies for your institution some questions to ask yourself and your partner in this process include 1) What is the setting for the study, 2) What scale was this study conducted on?, 3) was it published in a peer reviewed journal?, 4) What was the study design and sample size of the study?, 5) did it result in statistically significant results in the trial endpoints?.

Your partner in this process should be able to provide you with reliable, independently reviewed and published data from Tier IV or V to help you implement complementary measures that are easily adopted at large scale with minimal disruption to provide additional assistance to your current measures.

As always please feel free to comment or provide feedback below!