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

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          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.


          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.

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          Most cited references 24

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          The importance of the viable but non-culturable state in human bacterial pathogens

          Many bacterial species have been found to exist in a viable but non-culturable (VBNC) state since its discovery in 1982. VBNC cells are characterized by a loss of culturability on routine agar, which impairs their detection by conventional plate count techniques. This leads to an underestimation of total viable cells in environmental or clinical samples, and thus poses a risk to public health. In this review, we present recent findings on the VBNC state of human bacterial pathogens. The characteristics of VBNC cells, including the similarities and differences to viable, culturable cells and dead cells, and different detection methods are discussed. Exposure to various stresses can induce the VBNC state, and VBNC cells may be resuscitated back to culturable cells under suitable stimuli. The conditions that trigger the induction of the VBNC state and resuscitation from it are summarized and the mechanisms underlying these two processes are discussed. Last but not least, the significance of VBNC cells and their potential influence on human health are also reviewed.
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            A prospective study of the efficacy of routine decontamination for gastrointestinal endoscopes and the risk factors for failure.

            Patient-ready endoscopes were monitored over an 80-week period to determine the efficacy of decontamination procedures in a busy endoscopy center. Decontamination failure was related to patient and procedural parameters. Samples from patient-ready endoscopes were cultured aerobically and anaerobically and subjected to polymerase chain reaction (PCR) to detect hepatitis B virus (HBV), hepatitis C virus (HCV), and HIV. PCR to detect coliforms from 109 culture negative washes was used as a surrogate marker for biofilm in endoscopes. PCR was used to detect the presence of Helicobactor pylori in endoscopes used on infected patients. Procedural information such as biopsy retrieval, endoscope number, diagnosis, attending personnel, and decontamination system procedures was collected. Gastroscopes (n = 1,376) and colonoscopes (n = 987) were equally contaminated (1.8% vs 1.9%, respectively) with low numbers of organisms commonly isolated from the nasopharynx and/or feces. Only 1 wash contained viral nucleic acid (HCV). There was a significant correlation (P < .001) between the number of times a patient-ready endoscope was contaminated and its frequency of use. Colonoscopes used on patients with gastrointestinal disease were significantly more likely to remain contaminated through the decontamination process (P < .05). All other patient, staff, and decontamination system parameters remained not statistically significant. Coliform DNA was detected in 40% of culture-negative washes collected from patient-ready endoscopes, suggesting the presence of biofilm. No H pylori DNA was detected. Recommended decontamination procedures do not entirely eliminate persistence of low numbers of organisms on a few endoscopes, but this is unlikely to cause serious consequences in patients. Bacterial biofilm is difficult to remove and may explain this low-level persistence.
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              Longitudinal assessment of reprocessing effectiveness for colonoscopes and gastroscopes: Results of visual inspections, biochemical markers, and microbial cultures.

              Flexible endoscopes are currently reused following cleaning and high-level disinfection. Contamination has been found on endoscopes, and infections have been linked to gastrointestinal, respiratory, and urologic endoscopes.

                Author and article information

                1St. Boniface Research Centre , Winnipeg, MB, Canada
                2Department of Medical Microbiology, University of Manitoba , Winnipeg, MB, Canada
                3Department of Internal Medicine, University of Manitoba , Winnipeg, MB, Canada
                4Winnipeg Regional Health Authority , Winnipeg, MB, Canada
                5St. Boniface Hospital , Winnipeg, MB, Canada
                Author notes

                Edited by: Arun Chaudhury, GIM Foundation, United States

                Reviewed by: Madhukar Reddy Kasarla, Parkway Surgical and Cardiovascular Hospital, United States; Sunil Kumar, Neshoba County General Hospital and Nursing Home, United States; Sudheer Reddy Koyagura, Northwest Medical Center, United States

                *Correspondence: Michelle J. Alfa, malfa@

                Specialty section: This article was submitted to Gastroenterology, a section of the journal Frontiers in Medicine

                Front Med (Lausanne)
                Front Med (Lausanne)
                Front. Med.
                Frontiers in Medicine
                Frontiers Media S.A.
                07 November 2017
                : 4
                5681997 10.3389/fmed.2017.00191
                Copyright © 2017 Alfa, Singh, Nugent, Duerksen, Schultz, Reidy, DeGagne and Olson.

                This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

                Figures: 3, Tables: 3, Equations: 0, References: 28, Pages: 9, Words: 6632
                Funded by: American Society for Gastrointestinal Endoscopy 10.13039/100001947
                Award ID: 2015 Duodenoscope Infection Control Research Award from ASGE
                Original Research


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