A novel polytetrafluoroethylene-channel model, which simulates low levels of culturable bacteria in buildup biofilm after repeated endoscope reprocessing

Sterile Reverse Osmosis Water Combined with Friction Are Optimal for Channel and Lever Cavity Sample Collection of Flexible Duodenoscopes

“…As described by Alfa et al ( 20 , 21 ) BBF was formed over eight days at room temperature inside PTFE channels (Endoscopy Development Company, Maryland Heights, MO, USA) using ATS-2015 (Healthmark, Fraser, MI, USA) containing 8 Log 10 /mL (day 1) of E. faecalis and P. aeruginosa . On days 3, 4, and 5, the PTFE channels were rinsed and exposed to glutaraldehyde partial fixation (1:50 dilution of glutaraldehyde) and then repeat biofilm formation allowed to develop overnight ( 13 ).…”

“…Once the BBF was fully formed on day 8, there was full HLD of the BBF using 2.6% glutaraldehyde (Metricide ® from Metrex—Sybron Canada, Oakville, ON, Canada) for 20 min at room temperature. Segments (5 cm) of the fully formed BBF were cut from the full PTFE-BBF channel and attached in between two 60 cm sterile PTFE segments to form a “surrogate endoscope channel” (SEC) that was 125 cm long as described by Alfa et al ( 20 , 21 ). The SEC model was used to mimic low levels of organisms within the BBF that was only present in the central 5 cm portion of the total instrument channel length.…”

“…To assess the optimal method of obtaining a sample from the duodenoscope lever cavity the same inoculation method was used as described by Alfa et al ( 20 , 21 ). Briefly, ATS-2015 containing approximately 10 5 CFU/mL of both E. faecalis and E. coli was used to inoculate the lever cavity of both a JF-140F duodenoscope and a TJF-Q 180V duodenoscope with 0.1 mL of inoculum (total inoculum in lever cavity was 10 4 CFU).…”

“…For extraction from the lever cavity, a FBF method described by Alfa et al ( 20 , 21 ) was used and compared with recently recommended CDC method ( 16 ). The FBF method consisted of 1.0 mL of sterile reverse osmosis (RO) water instilled into the lever cavity (lever in raised vertical position) using a sterile plastic transfer pipette (Fisherbrand, Ottawa, ON, Canada), and the fluid was allowed to dwell in the cavity for 1 min.…”

Evaluation of an overnight non-culture test for detection of viable Gram-negative bacteria in endoscope channels

“…Culture of endoscopes is also fraught with additional standardization issues such as the sample collection method used (i. e. type of friction, type of extraction fluid, use of neutralizer) 9 10 11 12 13 and the culture protocol used (i. e. concentration of sample, culture media and duration of incubation) affect the sensitivity of cultures 9 10 11 12 13 14 15 16 17 . Although culture is recommended in many countries as a monitoring tool for endoscope reprocessing, 11 18 19 it is not currently recommended in United States guidelines 20 21 22 and there is evidence that there can be false-negative culture results 3 23 . Many of these issues might be avoided if rapid test methods could be used to reliably detect endoscope channel contamination post-high-level disinfection (HLD) but prior to patient use.…”