August 31, 2016 — In a surprising new study, researchers have found that gas relief drops may be contributing to infections on colonoscopes that remain dirty after being disinfected.
The study was conducted by researchers in Minnesota who noticed a white, cloudy, sticky substance on colonoscopes and gastroscopes that had been cleaned according to the manufacturers’ instructions.
When they tested the substance, they found simethicone, the active ingredient in gas relief drops. The drops are injected into scopes to eliminate bubbles inside the body that can impede visibility.
The problem is that the drops contain silicone, a waterproof substance that does not wash off or dissolve using disinfectants or detergents.
The drops also contain sugars and thickeners that “could provide the perfect habitat for the growth of bacteria” inside the scopes, the researchers warned.
Both of these ingredients could contribute to the growth of biofilm, in which bacteria stick together and become embedded in the surface of a medical device. With a layer of silicone trapping them inside tiny crevices, the scope would be nearly impossible to disinfect completely.
The risk has been known for years. In 2014, Pentax provided the following warning in their scope cleaning instructions:
“Due to their nature, these silicone-based agents cling tenaciously to surfaces. Unless they are rinsed very thoroughly, a barrier which could reduce the effectiveness of the disinfection/sterilization process could be created.”
The study was published in the American Journal of Infection Control. The researchers recommended “minimizing the use of simethicone pending further research into its safety.”