Evaluation of Cleaning Efficacy and High Level Disinfection whem Removing Biofilm from Endoscopes Channels

Background: Endoscope is equipment approved to be reused in spite of its complex internal structure, consisting of long channels with narrowed lumens, allowing adherence of organic material and microorganisms, favoring formation of biofilm, making difficult an effective procedure, which is a challenge in the reuse of this equipment. The biofilm formation during endoscopic procedures is inevitable and it is very difficult to entirely remove it. Consequently, recent researches report it as the probable factor responsible by transmissions of exogenous infections and for the side effects found in patients submitted to gastrointestinal endoscopy procedures. This picture brought the concern to eradicate it.

Objective: to evaluate the action of high level disinfection to remove biofilm after prior cleaning and brushing in body samples, simulating flexible endoscopic channels and to compare products commercially available in the national market to remove the biofilm from endoscopes.

Methods: New transparent tubes with internal politetrafluorethylen (Teflon™) lining, 1,2m long, with an internal diameter of 2,8mm, were used to simulate the suction/biopsy canals of the endoscope.The bacterium used for this study was Pseudomonas aeruginosa (ATCC 27853), as a test microorganism to form the biofilm. A validated model was designed to develop the biofilm. The contaminated body samples were initially submitted to manual cleaning process with enzymatic cleansing and brushing. Next, these bodies were submitted to five high-level disinfection methods, as follows: peracetic acid at 0.09% and 0.15% of concentration, Steris™ System, 2% glutaraldehyde and acid electrolytic water. Three segments were removed, measuring approximately three millimeters, representing the beginning, the middle and the end of each body sample. These segments were analyzed by means of screening electronic microscopy in relation to biofilm presence.

Results: no tested method removed 100% of biofilm and this removal depends on the interaction between the cleaning method and later disinfection. It was observed that the most effective procedure to physically remove the biofilm was the automatic flexible endoscope reprocessors which allows the additional of a cleaning cycle and disinfection in 2% glutaraldehyde. Conclusions: Regarding new technologies available for processing endoscope channels, none of the tested methods in the present investigation was totally effective to remove biofilm in face of the challenge presented So, we may suggest that the good practices recommended by the several existing societies be strictly followed, in spite of the time needed for this process. Automated process is suggested as the best option to decrease human error.