Contribution of usage to endoscope working channel damage and bacterial contamination

Background: Biofilm formation has been shown to be associated with damaged areas of endoscope channels. It was hypothesized that the passage of instruments and brushes through endoscope channels during procedures and cleaning contributes to channel damage, bacterial attachment and biofilm formation. Aim: To compare surface roughness and bacterial attachment in used and new endoscope channels in vivo and in vitro. Methods: Surface roughness of 10 clinically used (retired) and seven new colonoscope biopsy channels was analysed by a surface profiler. For the in-vitro study, a flexible endoscope biopsy forceps was passed repeatedly through a curved 3.0-mm-diameter Teflon tube 100, 200 and 500 times. Atomic force microscopy was used to determine the degree of inner surface damage. The number of Escherichia coli or Enterococcus faecium attached to the inner surface of the new Teflon tube and the tube with 500 forceps passes in 1 h at 37 degrees C was determined by culture. Results: The average surface roughness of the used biopsy channels was found to be 1.5 times greater than that of the new biopsy channels (P=0.03). Surface roughness of Teflon tubes with 100, 200 and 500 forceps passes was 1.05-, 1.12- and 3.2-fold (P=0.025) greater than the roughness of the new Teflon tubes, respectively. The number of E. coli and E. faecium attached to Teflon tubes with 500 forceps passes was 2.9-fold (P=0.021) and 4.3-fold (P=0.004) higher compared with the number of E. coli and E. faecium attached to the new Teflon tubes, respectively. Conclusion: An association was found between endoscope usage with damage to the biopsy channel and increased bacterial attachment. (C) 2020 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.