The number of endoscopy related infections and outbreaks has increased rapidly over the last few years. Previous study demonstrated biofilm formation associated with damaged areas of endoscope channels (1). Protection of bacterial biofilms within pits and scratches of endoscope channels makes cleaning difficult, contributes to endoscope contamination and pathogen transmission.
We hypothesis that the passage of instruments and brushes through endoscope channels during procedures and cleaning contribute to the channel damage, bacterial attachment and biofilm formation. In this study, we compared the roughness and bacterial attachment in used endoscope channel compared to new endoscope channel in vivo and in vitro.
The surface profiles of ten clinically used retired and seven new colonoscope biopsy channels were analysed by contact profilometer.
For in vitro study, a flexible endoscope biopsy forceps with 2.8 mm of diameter was repeatedly passed through a curved 3.0 mm diameter Teflon tube 100, 200, 500 times. Atomic force microscopy was used to determine the degree of inner surface damage.
10^8/ml Escherichia coli or Enterococcus faecium culture was circulated in an enclosed flow system containing new Teflon tube and tube with 500 times biopsy forceps passes for one hour at 37oC. Bacteria attached to the inner surface of Teflon tube was determined by colony forming units.
Average surface roughness of clinically used colonoscope biopsy channels was 3.7-fold of the new colonoscope biopsy channels (P=0.03). Surface roughness of Teflon tubes with 100, 200 and 500 times biopsy forceps passes was 1, 1 and 3.2-fold (P=0.025) of the new Teflon tubes respectively.
The bacterial number of E. coli and E. faecium attached to Teflon tubes with 500 times biopsy forceps passes was 2.9-fold (P=0.021) and 4.3-fold (P=0.018) of the bacterial number attached to the new Teflon tubes respectively.
Our study confirmed the association of endoscope usage with biopsy channel damage and increased bacterial attachment. The endoscope channel after 500 times of usage posed a great risk of bacterial contamination, pathogen transmission and should retire.