The Use of ATPase Monitoring to Determine Endoscope Bioburden and Assure Satisfactory Manual Cleaning

Abstract

Introduction: Recent multidrug resistant organism outbreaks linked to endoscopy have prompted re-examination of endoscope reprocessing. The steps of reprocessing include manual cleaning, automatic reprocessing, and drying. The manual cleaning phase is the most vulnerable to contamination as it is prone to human error. Many centers have turned to culturing instruments to assure that their instruments have been successfully disinfected. We report applying the “ATPase” assay to our reprocessing method. This technology is routinely used in hospitals to assure cleanliness of work surfaces but it is sparingly used in the field of endoscopy. The system provides real-time, quantitative data by utilizing bioluminescence of adenosine triphosphate (ATP) as an indirect measure of bacterial presence or bioburden. There is no standardized method of ATPase use in endoscopy. Methods: Data was collected from patient used colonoscopes and gastroscopes during a 3 month trial period. Data was then collected over the following 12 months after the reprocessing method was reformed. ATP samples were obtained after intruments were manually cleaned, just before they were placed into an automatic reprocessor. A collection technique proposed by a leading investogator in the field was used to obtain channel and surface samples. The 3M™ Clean-Trace ATP Surface Test was used to measure the presence of ATP. A threshold of 200 relative light units (RLU) was used to determine if endoscopes “passed”. Instruments were re-cleaned if they exceeded 200 RLU. Results: A total of 618 tests were performed (310 gastroscopes) between March 2013 and May 2014. Surface cleaning was effective in 98.5% of gastroscopes and 96.9% of colonoscopes. Samples obtained from the biopsy channel were quite different with 95.4% of colonoscopes passing and only 64.2% of gastroscopes passing. The manual cleaning process was then modified and the enzymatic detergent used to flush endoscope channels was changed. During the 12 month observation period, over 90% of all gastroscopes and colonoscopes passed. Conclusion: Initial results showed that gastroscopes were more difficult to clean, likely due to biofilm on complex structural elements and increased mucus encountered during EGD. After modifying the reprocessing technique, the RLU values for gastroscopes significantly improved. We provide this data to aid in the standardization of the ATPase assay sampling method as a routine method of manual cleaning phase monitoring at endoscopy centers worldwide.