Cleaning Scopes and Instruments With Enzymatics: Thoughts From Marc Esquenet of The Ruhof Corporation

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This article was written by Marc Esquenet, VP Research and Development, The RUHOF CORPORATION, U.S.A. Learn more about THE RUHOF CORPORATION here.

The field of endoscopy encompasses a wide range of procedures that require very specific types of scopes. Because more than 30 unique scopes are needed for these various procedures, a reprocessing technician must be prepared for many challenges. More specifically, with so many different types of scopes on the market, the instructions for reprocessing are very different and can make the cleaning process confusing, time-consuming and cumbersome. Due to the complex design features of the different types of endoscopes, it is important to note that there are numerous cleaning challenges that cause confusion or uncertainty.  

For the purpose of this article, we will focus on the area of enzymatic detergents and attempt to eliminate any associated concerns. First, we will discuss the importance of using an enzymatic detergent in the scope cleaning process. Second, we will discuss how specific types of soils have recently emerged as "next to impossible to remove," and how new enzymatic detergent technologies and validation studies have been developed to confront this specific challenge to cleaning endoscopes. Most importantly, we will help endoscopy professionals ask the right questions when selecting an enzymatic detergent to use in their department.

What makes enzymatic detergents effective

Let's start with identifying what has made enzymatic detergents unique and superior cleaners in the area of endoscopy reprocessing. In order to prepare endoscopes for reuse, they must be cleaned and then exposed to a high-level disinfectant. The cleaning part of the preparation process requires the use of a detergent that is neutral pH, well-balanced, and is able to digest combined protein-fat-carbohydrate soils. Enzymatic cleaners — multi-tiered cleaners in particular — are extremely effective in removing soil and organic matter.

Enzymatic detergents are generally near-neutral pH and are not corrosive to endoscopes. Additional ingredients in enzymatic detergents include solubilizing agents, soil-suspending agents, and surfactants with good wetting properties, chosen to enhance enzymatic action and contribute to the product's effectiveness. The unique and highly differentiated enzyme combinations in high-quality enzymatic detergents can effectively digest all of the intertwined components of the organic soil "matrix."

Hydrolysis (break down due to a reaction with water) of protein enhances the degradation of fats and carbohydrates. Digestion of carbohydrates likewise allows faster and more complete protein and lipid hydrolysis. Lipid digestion enables enhanced protein and carbohydrate digestion.  Lipase is particularly valuable in endoscope cleaning because it digests the fat, whereas surfactants may partially remove fat, but do not digest it or prevent it from redepositing.

A highly developed enzymatic product should be clinically proven to be more effective at removing organic matter (bioburden) than non-enzyme-based or limited enzyme-based cleaning products. It should be noted that department heads evaluating an enzymatic detergent ask for independent laboratory validation studies that can prove the product's efficacy at the recommended dilutions. 

The history of enzymatic detergents

Enzymatic detergents, for the purpose of cleaning endoscopes, were first developed in 1976. The original enzymatic detergent product was a single enzyme powder detergent. At that time, there was never a real discussion regarding the types of soils that needed to be removed from endoscopes. It was understood that the soil to be removed was organic and that enzymes were very good at quickly breaking down the soil into a liquefied state. The powder product, known as Protozyme and developed by the Ruhof Corporation, was a single enzyme product with surfactants. The product was highly more effective at removing organic material from an endoscope when compared to the common "green-colored soap" used at the time.

When using the new enzyme-based detergent for the first time, technicians realized that their scopes "smelled" cleaner and felt "less greasy."  While the idea of a cleaner-smelling scope was great, the idea of "less greasy" was a clear indicator that a more highly-developed enzymatic detergent was required so that any type of greasy feel could be completely eliminated. At this juncture, it was understood that the soils to be removed were more complex than originally thought.
New multiple enzyme detergents (multi-tiered) were developed that would be aggressive enough to eliminate the many organic components found on an endoscope, but that were also very delicate and compatible to the many types of materials used in the construction of endoscopes. At this point, the industry referred to the complex organic soil as "bioburden."

That was more than 30 years ago. Since then, the soils have not changed; rather, the difficulties with removing the soils have been better identified. In the 21st century, new aspects of the organic soil that contaminates endoscopes has been identified as contributing to major cases of cross-contamination. Situations have arisen where proper reprocessing steps have been followed and yet the scopes still are contaminated.

Tackling biofilm and bioburden

The contributing factor to ongoing contamination has been the identification of "biofilm." Biofilm has recently been classified as a target soil for elimination from endoscopes, in addition to the previously identified "bioburden." New, highly advanced, neutral pH multi-tiered enzymatic detergent technologies, designed to specifically target and dissolve the insoluble polysaccharide outermost layer of biofilm have been developed. Dissolving this outermost layer allows for the complete elimination of all bioburden and biofilm on semi-critical and critical medical devices by high-level disinfectants or liquid chemical sterilants. This new enzymatic detergent technology has been developed to aide in eliminating the challenges presented by biofilm.

When selecting an enzymatic detergent to use in a facility, the person or committee in charge should consider selecting a detergent that is clinically tested to aid in the complete removal of both bioburden and biofilm. To qualify this product for selection, the detergent manufacturer must be able to provide evidence that both types of soils can be removed according to some type of internationally recognized standard.  ISO15883 offers tests methods to evaluate the detergent efficacy for the removal of bioburden. 

How should you choose a detergent?

To date, ISO15883 Annex F is the only standard available to show the efficacy of a detergent in the removal of bioburden and biofilm. Therefore, when evaluating a detergent to use for your department, the following enzymatic detergent specifications should be met: 

• Clinically tested to pass ISO 15883 Annex F (i.e. solubilizes polysaccharides during the cleaning process allowing for high level disinfectants to kill and remove biofilm).  
• Contain a multi-tiered blend of enzymes designed to remove all bio-burden — blood, carbohydrates, protein, polysaccharides, fats, oils, uric acid and other nitrogenous compounds.
• Clinically tested to remove 99.9 percent of all bioburden
• Capable of eliminating odors from scopes, instruments and washers and be safe for use on all scopes
• Low-sudsing, pH neutral, non-abrasive, free rinsing and readily biodegradable

There are many different enzymatic detergents designed to clean scopes and instruments on the market today. Considering what we know about the difficulty of cleaning scopes and instruments, be sure to select a detergent consisting of a multi-tiered blend of enzymes designed to be effective for the cleaning challenges presented by both bioburden and biofilm. A multi-enzymatic detergent is truly the best product for increasing overall cleaning effectiveness and decreasing the likelihood of cross contamination in your facility.    


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