Introduction
In otorhinolaryngology (ORL), flexible endoscopes without a working channel (FEs) are used to examine the nasal cavity, pharynx and larynx. FEs are frequently used and thus reprocessed several times a day. Previous research demonstrated that contamination with secretions, blood and microorganisms after use can be extensive(1). Inadequate reprocessing of endoscopes is considered the most important factor of contamination from endoscopy procedures, possibly resulting in outbreaks of health-care-associated infections(2). Therefore, thorough reprocessing of FEs is critical for limiting pathogen transmission and reducing infections.
To determine the strategy for sterilization or disinfection of a specific medical devices, the level of disinfection is determined. There are three disinfection levels: high, intermediate and low-level disinfection. Each disinfection level can be distinguished from one another based on the specific marker or indicator microorganisms that each can or cannot destroy. According to Spaulding’s classification scheme, FEs are considered semi-critical medical devices and require high-level disinfection(3).
Several standard guidelines for reprocessing endoscopes have been developed by several professional organizations, such as the European Society for Gastrointestinal Endoscopy(ESGE), the American Society for Gastrointestinal Endoscopy(ASGE), the Healthcare Infection Control Practices Advisory Committee(HICPAC) and the Dutch Flexible Endoscopes Cleaning and Disinfection Steering Committee(SFERD) or guidelines are provided by the manufacturer of the FEs(4-7). No international standard has been implemented and the methods used are often time-consuming. This could lead to longer waiting times for patients, or additional costs, because the long reprocessing times require more FEs in inventory. In addition, large amounts of water and chemicals are used. Disinfection with ultraviolet light(UVL) could be an alternative method.
UVL can be divided into three groups depending on the length of their bands: A(315-400 nm), B(280-315 nm) and C(100-280 nm)(8). UVL group C(UV-C) is known to be the most harmful to living organisms, with peak efficiency at 254nm(8).
Previous research has shown that UVL disinfection of medical surfaces can be highly effective in reducing microorganisms, such as Clostridium difficile, Methicillin-resistant Staphylococcus aureus (MRSA), biofilm-forming bacteria and fungal spores(9-12). UV-C light disinfection for ORL endoscopes showed a bacterial reduction of 106 Colony Forming Units(CFUs) for rigid endoscopes and a 107 CFU reduction for FEs(13, 14).
The current reprocessing method for FEs is done using water and chemicals with the Endoscope Washer Disinfector (EWD). However, this process is time-consuming and should therefore be improved. UV-C light disinfection has shown to be a promising tool for surface and endoscope disinfection in previous research. The goal of this study was to investigate the CFU reduction on contaminated FEs without a working channel after UV-C light disinfection, compared to the current disinfection method with the EWD.