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

INTRODUCTION: Simulated-use buildup biofilm (BBF) model was used to assess various extraction fluids and friction methods to determine the optimal sample collection method for polytetrafluorethylene channels. In addition, simulated-use testing was performed for the channel and lever cavity of duodenoscopes. MATERIALS AND METHODS: BBF was formed in polytetrafluorethylene channels using Enterococcus faecalis, Escherichia coli, and Pseudomonas aeruginosa. Sterile reverse osmosis (RO) water, and phosphate-buffered saline with and without Tween80 as well as two neutralizing broths (Letheen and Dey-Engley) were each assessed with and without friction. Neutralizer was added immediately after sample collection and samples concentrated using centrifugation. Simulated-use testing was done using TJF-Q180V and JF-140F Olympus duodenoscopes. RESULTS: Despite variability in the bacterial CFU in the BBF model, none of the extraction fluids tested were significantly better than RO. Borescope examination showed far less residual material when friction was part of the extraction protocol. The RO for flush-brush-flush (FBF) extraction provided significantly better recovery of E. coli (p = 0.02) from duodenoscope lever cavities compared to the CDC flush method. DISCUSSION AND CONCLUSION: We recommend RO with friction for FBF extraction of the channel and lever cavity of duodenoscopes. Neutralizer and sample concentration optimize recovery of viable bacteria on culture.

A new buildup biofilm model that mimics accumulation of material in flexible endoscope channels.

The objective of this study was to develop a new build up biofilm (BBF) model that was based on repeated exposure to test soil containing Enterococcus faecalis and Pseudomonas aeruginosa and repeated rounds of fixation to mimic the accumulation of patient material in endoscope channels during reprocessing. The new BBF model is a novel adaptation of the minimum biofilm effective concentration (MBEC) 96-well model where biofilm is formed on plastic pegs. The new MBEC-BBF model was developed over eight days and included four rounds of partial fixation using glutaraldehyde. There was 6.14Log10cfu/cm(2) of E. faecalis and 7.71Log10cfu/cm(2) of P. aeruginosa in the final BBF. Four detergents (two enzymatic and two non-enzymatic) were tested alone or in combination with orthophthalaldehyde, glutaraldehyde or accelerated hydrogen peroxide to determine if BBF could be either removed or the bacteria within the BBF killed. None of the detergents alone could remove the biofilm or reduce the bacterial level in the BBF as determined by viable count and scanning electron microscopy. The combination of detergents and disinfectants tested provided a 3 to 5Log10 reduction in viable bacteria but no combination could provide the expected 6Log10 reduction. Our data indicated that once formed BBF was extremely difficult to eliminate. Future research using the BBF model may help develop new cleaning and disinfection methods that can prevent or eliminate BBF within endoscope channels.