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Editor’s note:
Editor’s note: The following work represents the preliminary work being performed by the authors. The study was sponsored by Process Cleaning Solutions (PCS)
Disclosures: The authors of this article are employees of CremCo Labs.
Abstract
Background
High-touch environmental surfaces (HITES) can be vehicles for healthcare-associated infections (HAI). However, their decontamination by wiping is rarely assessed reflecting field use. Here, we report the development and application of a new carrier platform to quantitatively assess HITES decontamination by wiping with a microfiber-based fabric dampened with a neutral pH solution (~ 200 ppm chlorine) of hypochlorous acid (PCS).
Materials & Methods
The platform (30 cm X 60 cm) was custom-designed and made out of Teflon with perforations to separately imbed nine carrier disks in it. Each disk (1 cm diam.; 0.7 mm thick) of brushed stainless steel was individually placed into the holes for a tight fit and the platform sterilized by autoclaving. Six of the disks received 10 µL of a Staphylococcus aureus (ATCC 6538) suspension (>106 CFU) in a soil load, and the inocula dried under ambient conditions for two hours. Three of the disks were left uncontaminated to assess any transfer of contamination during wiping. For decontamination, the entire platform was wiped in two steps with a dampened microfiber fabric in a field relevant manner. After 30 seconds the disks were then retrieved directly and simultaneously into separate vials containing 10.0 mL of an eluent/diluent/neutralizer. The eluates were assayed for CFU by membrane filtration and log10 reductions calculated. Normal saline with 0.1% Tween-80 (saline-T) was used as a control solution for wiping.
Results
This preliminary testing showed the platform to keep the disks in place during wiping and also allowed the wiping itself to better represent the decontamination process in the field. Wiping with the hypochlorous acid disinfectant brought the contamination to an acceptable level (>5 log10 reduction) with no transfer of contamination to clean disks.
Conclusion
The device and the protocol described can quantitatively determine HITES decontamination in a field relevant manner. The platform and the decontamination process are also potentially applicable to not only other kinds of carrier materials but also to assess HITES decontamination using other classes of pathogens implicated in HAI. The use of microber fabric greatly reduced the number of CFU, but was further enhanced by the addition of the hypochlorous acid.
Last Updated: June 18, 2017, 9:52 AM EST
Graeme Marsh
Here are some initial thoughts and responses:
(i) Hypochlorous Acid is a product that is still rooted in the mindset that all germs are bad, and so work on a “kill everything” approach, where the much needed beneficial bacteria are indiscrimantly removed along with the unwanted pathogens.
This runs contrary to the research over the past few years into the indoor microbiome which argues for the bio-engineering of indoor surfaces to be abundant in beneficial bacteria, (U of OR and U of Chicago for instance). As Prof Jessica Green noted in one of her TED Talks, we need “yogurt” for buildings; in other words a beneficial, supportive indoor microbiome.
By “killing everything” such indiscriminate chemical cleaners leave a biological vacuum that can more often than not rapidly be re-colonized by pathogens, especially of biofilm is not addressed. If biofilm is not addressed, pathogens can quickly re-colonize an area “cleaned” with such chemical cleaners, usually within 2 to 4 hours.
(ii)There are many different types of “microfiber”; at the high end are denier cloths, such as Perfect Clean’s products; the next tier comprises like Tietex that that prevent quat binding, and then there are the bulk, mass market offerings at the lower end. Which is used can be crucial in determining effectiveness; (Darrel Hicks stresses the use of denier cloth in much of what he has written).
So the question then comes down to how much of the work is done by the microfiber cloth, and that in turn is dependent upon the quality of the microfiber.
(iii) Probiotic cleaners are pH neutral cleaners that utilize the principle of Competitive Exclusion; they over populate surfaces with beneficial probiotics that deprives pathogens of food, and in the process the probiotics produce biosurfactants that keep on breaking down microscopic layers of contamination well beyond application. In this way they provide a unique ongoing process of cleaning that can last for up to a couple of days in the right conditions.
Furthermore, probiotic cleaners have a unique capability to seek out a food source across a surface and into those microscopic “nooks and crannines” and tight edges that wet mopping / wet wiping fail to get to. This unique motility that probiotics offer provides a much more comprehensive surface cleaning.
In essence probiotic cleaners represent Nature’s means of addressing the biological problem of pathogens, with an appreciation that not all bacteria are harmful, rather it is critical that we keep a presence of beneficial bacteria on surfaces to make those surface unsupportive of pathogens.