Efficacy of routine fiberoptic endoscope cleaning and disinfection for killing Clostridium difficile

We have evaluated a standard procedure for cleaning and disinfection of endoscopes for efficacy in eradicating a spore-forming bacterial organism, Clostridium difficile. Initially, 23 endoscopes were cultured for the presence of C. difficile after hanging in storage for at least 24 hours after cleaning and disinfection. All cultures were negative. Subsequently, endoscopes used in 15 patients who had stool cultures positive for C. difficile were cultured immediately after use and again after cleaning and disinfection with 2% alkaline glutaraldehyde for 5 min. Ten of 15 (67%) endoscopes were culture positive for C. difficile immediately after use. After cleaning and disinfection, all of the endoscopes were culture negative except one, which yielded two negative cultures and two cultures showing late growth of rare C. difficile colonies, but contamination could not be ruled out. In vitro exposure to 2% alkaline glutaraldehyde for 5 min resulted in 99% or greater killing of C. difficile spores. We conclude that cleaning and a minimum of 5 min of disinfection with 2% alkaline glutaraldehyde are likely to be effective in killing C. difficile vegetative organisms and spores on endoscopes.