7. Project Summary/Abstract Outbreaks associated with contaminated duodenoscopes are still occurring at high rates. Recent clinical studies evaluating patient?used endoscopes reported that culture endoscope contamination rates range from < 1% up to 20%. Experts now recognize that there is an urgent need for an inexpensive and highly reliable sampling method to check on the adequacy of reprocessing duodenoscopes. NovaFlux has developed a novel method utilizing two?phase flow (TPF) to extract material from channels of flexible endoscopes using a mixture of filtered air and sterile reverse osmosis water. Preliminary testing indicates that the efficacy of this method provides a detection level that is similar to extraction methods that use destructive testing of build?up biofilm within narrow channels. The channel extraction process used for the TPF method is based on a ?closed? system, thereby reducing the risk of introducing external contamination of the sample collected or the endoscope. This technology will improve both the integrity of the sample as well as the sensitivity of extraction from channels of patient?used endoscopes. We propose to develop a duodenoscope sampling system based on two?phase flow extraction technology to obtain a reliable sample for culture and chemical analysis (protein and carbohydrate). The TPF sampling system will be tested with the most challenging traditional biofilm (TBF) and build?up biofilm (BBF) prepared from a mixture of organisms representative of those that may contaminate duodenoscopes. The TPF duodenoscope sampling system includes two main components: 1) a TPF mixture generation device, and 2) a complete sterile tubing kit. The TPF sampling system is designed to extract contaminants from the surfaces of all the channels, without brushing, including the suction/biopsy channel and the narrow air/water channels, as well as the surfaces of the elevator assembly including the lever recess. A special ?Lever Assembly Sampling Fixture? has been designed to fit around the endoscope distal end and harness the high?velocity droplets exiting the channels to direct them to impinge over the surface of the lever mechanism of the duodenoscope. The two?phase technology is based on a 1000:1 air?to?sterile water volumetric ratio which can travel at high velocities (20 to 60 m/s) in narrow endoscope channels. In this flow regime, the liquid transforms into high velocity droplets that impact the surface of the channels with forces that are approximately 10 to 100 times higher than those which can be obtained from a simple liquid flow at the same pressure drop. A second main advantage of TPF extraction arises from the very high number of times that the surface of a channel can be treated with droplets in a short time. We estimated that the surface of an endoscope channel is treated about 2000 times in 10 minutes. The volumetric flow rate air used to sample the endoscope channels with TPF is high ~ 100 liters/minute at standard temperature and pressure. The Specific Aims are to: 1) compare TPF sampling of build?up biofilm versus destructive testing, 2) compare TPF sampling with the new FDA/CDC/ASM protocol in duodenoscopes with high and low CFU challenge, and 3) develop the design of the TPF sampling system based on the results of channel and endoscope testing.
NIH ExPorter
NIH ExPorter