I think with advancement and by this I mean our ability to manufacture “better” disinfectants, our ability to improve test methods both for disinfectant product efficacy but also for clinical specimen sampling and disease diagnosis we become so enlightened with all the “new” stuff we forget the importance of the basics. I think we often need to be reminded of the basics.
While there is sufficient published science to support that sodium hypochlorite at the correct dilution and contact time has the ability to kill C.diff spores, it has not been until recent years that Health Canada or the US EPA has approved a method to allow for actual label claims against C.diff. We can now choose from sodium hypochlorite, hydrogen peroxide and peracetic acid based formulations with registered claims against spores. Certainly, from an infection prevention perspective this has meant advancement in practices, but in the quest to find products that can KILL we have lost sight of the importance of physical friction. More simply put, we have lost sight of the importance of how CLEANING, how WIPING can and WILL remove spores from the surface.
Let’s be honest, to kill spores we need to increase the concentration of chemical used. This increase will result in less than stellar occupational health and safety profiles for the products that are being used and will also have a direct impact on the compatibility with the various surfaces the product will be applied.
The 2010, SHEA-IDSA Guidelines for Clostridium difficile states “The efficacy of cleaning is critical to the success of decontamination in general, and thus user acceptability of disinfection regimens is key issue”. When asked about a product’s ability to kill, I have always stated that I do not care what a product kills, if staff will not use the product as designed by the manufacturer, the label claim is meaningless! Don’t get me wrong, I am in no way saying that we should not use sporicidal agents in dealing with C. diff. What I am saying is that we need to consider more that what the product kills, but look at how effective the product is at cleaning (thereby removing spores from the surface) and most importantly, how will the staff that will be using these products daily for long periods of time respond? A well implemented infection control program requires that the products we choose are in fact used!
It was with this that I was quite excited to read a recently published study by Dr. William Rutala and his research team (ICHE,2012;33:1255-1258). The study compared the importance of physical removal versus sporicidal inactivation of different cleaning and disinfection chemistries. There was what I thought of as several key take home points – or “Ah-Ha” moments. First, did you know that most studies have quantitated the level of C. diff spore contamination on surfaces to be <1Log10? Why then do Health Canada and the US EPA require manufactures to achieve at least a 6 Log10 reduction against C.diff spores in order to make a claim. If you didn’t already know, a 6 log10 reduction implies we are chemically sterilizing the surface. If we do not have that level of contamination on surfaces to begin with why do disinfectants need to achieve such a level of kill? As mentioned earlier, to obtain sporicidal claims we need to increase the concentration of chemical used. We are creating disinfectant products that have increased occupational risks. Perhaps if the test method needed to obtain a sporicidal surface claim was adjusted to provide a more realistic level of kill based on actual surface contamination we would have sporicidal products that we could use on a daily basis without the worry of occupational safety or material compatibility issues.
Secondly, and to me most importantly, CLEANING WORKS! The study showed that wiping environmental surfaces, even with a non-sporicidal agent can eliminate approximately 3 Log10 of C.difficile spores. Sporicidal agents provided a 3 Log10 to 6 Log10 reduction depending on formulation and/or application with the most commonly used bleach wipe showing just under a 4 Log10 reduction.
I’m not saying that we shouldn’t use sporicidal agents. I’ve worked with enough facilities in outbreak situation to know they work. However, have we set the bar to high in terms of what is required with respect to obtaining a registered C. difficile claim? Are we knowingly, exposing our staff to unnecessarily high concentrations of chemicals when as we know the level of contamination on surfaces is significantly lower than the level of kill required to obtain a label claim? Knowing that cleaning works, would we be wrong to develop protocols that focus on the physical removal of spores for cleaning of isolation rooms and utilize sporicidal agents for terminal cleaning, for outbreaks or for use on wards with higher endemic levels of C. diff? I know facilities that do just that and do it well.
Food for thought, I hope!