Bacteriologic testing of endoscopes after high-level disinfection

Abstract

Background There are no definitive data available concerning microbiologic safety of prolonged endoscope storage after reprocessing and disinfection. This study evaluated the durability of high-level disinfection of endoscopes stored in a dust-proof cabinet for 5 days. Methods Three different types of endoscopes (upper endoscopes, duodenoscopes, colonoscopes) were tested. After completion of the endoscopic procedure, endoscopes were subjected to an initial decontamination, followed by manual cleaning with the endoscope immersed in detergent. The endoscopes then were placed in an automatic reprocessor that provides high-level disinfection. They then were stored by hanging in a dust-proof cabinet. Bacteriologic samples were obtained from the surface of the endoscopes, the openings for the piston valves, and the accessory channel daily for 5 days, and by flush-through (combined with brushing) from the accessory channels after 5 days of storage. Samples were cultured for all types of aerobic and anaerobic bacteria, including bacterial spores, and for Candida species. Results For all assays, all endoscopes were bacteria-free immediately after high-level disinfection. Only 4 assays (of 135) were positive during the subsequent 5-day assessment (skin bacteria cultured from endoscope surfaces). All flush-through samples were sterile. Conclusions When endoscope reprocessing guidelines are strictly observed and endoscopes are stored in appropriate cabinets for up to 5 days, reprocessing before use may not be necessary.