From its inception, the intent of the Talk Clean to Me
blog has been to educate about the choice and use of disinfectants. The content of our blogs are based on fact
drawing from a myriad of published sources and smattered with analogies or
stories of direct experiences and we hope a bit of humour. If we go back to the original blogs from the
Spring and Summer of 2011, we started off weaving a story of the desired traits
of a disinfectant targeting key areas to consider when choosing a product.
Understanding that some may think the blog a bit self
serving as both Lee and I work for a
disinfectant manufacturer, it's rewarding to read Drs Rutala and Weber's
article published in ICHE this July titled "Selection of the Ideal Disinfectant"
as it highlights many of the same points we have been talking about since we
launched Talk Clean to Me.
Over the next several weeks, I will try to summarize the
article and invite everyone to read it as it is truly a landmark piece that
embodies the attributes that anyone who is choosing a disinfectant should
consider. As hinted in my title, the
focus of this blog will be on the first section "Kill Claims For the Most
Prevalent Healthcare Pathogens" which closely resembles the idea behind
our "Strength in Not Always Found in Numbers" blog.
As Rutala and Weber highlight, the disinfectant product
selected should be one that is effective against the pathogens that cause HAIs,
and vegetative bacteria such as S. aureus, Enterococcus, E. coli, Klebsiella,
Pseudomonas and Enterobacter have been found to cause almost 80% of all
HAIs. I hope you'll take a look at Table
3 from the article as it summarizes the most prevalent pathogens that cause
HAIs very nicely. Basically, the marketing ploy by some disinfectant manufacturers
focuses on who has the greatest NUMBER of claims, not who has the most
APPLICABLE claims....inferring that they are the most effective product is a
carefully crafted game of smoke and mirrors.
The next important area to understand is with respect to
antibiotic resistance. Without a
doubt, antibiotic resistance is a
concern from a treatment perspective. As
we touched upon in our "Doors, Keys and Sledgehammers " blog and
confirmed by Rutala and Weber, disinfectant testing for antibiotic-resistant
organisms is not necessary, as antibiotic resistant pathogens are not more
resistant to disinfectants than antibiotic sensitive pathogens. There are however, some pathogens that are
intrinsically more resistant to disinfectants than others which leads me to the
third, and I think most important discussion of this section of the article -
the concept of the order of susceptibility of microorganisms to disinfectants.
When considering disinfectants, we also need to consider
the hierarchical scale of susceptibility.
The original hierarchy was developed by Spaulding in 1957 and is still
widely cited in guidelines and policies, however, our understanding of
pathogens and their susceptibility to disinfectants has dramatically
improved. Rutala and Weber have proposed
a new hierarchy which I completely concur with based on my experience of
conducting efficacy testing on a number of different disinfectant actives. Regardless of the hierarchical scale you
choose to follow it is imperative to understand that this is only a guide and
that the efficacy of disinfectants to pathogens will vary depending on the
disinfectant active as well as how the product is formulated (e.g. 2
Quat-Alcohol products with different formulations can have widely varied kill
claims and contact times). As outlined
in the article, a non-sporicidal disinfectant with a TB claim which
traditionally was considered the most resistant vegetative bacteria does not
mean that the product will have the ability to kill small, non-enveloped
viruses such as Norovirus or Poliovirus.
Another area where the hierarchy should be considered is
with emerging pathogens such as MERS-CoV or Enterovirus D68. Emerging pathogens generally mean that there
is not an approved test methodology for a disinfectant to obtain efficacy
claims by the EPA. In cases such as this
where the microbiologic class has been established, than an already approved
surrogate could be used. For example,
claims against Human Coronavirus would be appropriate to ensure efficacy
against MERS-CoV or as in our "H1N1, H5N1, H10N8, H7N9 - What Influenza strain will we see next? " blog, proven efficacy against 1 strain of
Influenza A would be sufficient to assume efficacy against emerging strains of
influenza.
Lastly, for viruses where the microbiological class has
not yet been determined (e.g. when SARS first hit or Ebola where there is no
test method to determine efficacy) then we would look for efficacy against the
heartier non-enveloped viruses.
Typically in these situations efficacy against Poliovirus, Adenovirus,
Rhinovirus or Canine Parvovirus would be considered as this viruses are known
to be more resistant to disinfectants than others.
As Drs. Rutala and Weber so eloquently stated "using
this accumulated knowledge of microbiological susceptibility should discourage
unnecessary testing, listing irrelevant organisms on labels and avoid
"bug-of-the-month" testing".
Stay tuned for next week's blog which will focus on the
second section "Fast Kill Times and Acceptable Wet-Contact Time To Ensure
Proper Disinfection of Non-Critical Surfaces and Patient Care Equipment".
Bugging Off!
Nicole
