Biofilm in Endoscopy

Biofilm in Flexible Endoscopes

A new endoscope does not contain biofilm but shortly after the first use, a conditioning film is created on the biomaterials of the endoscope. The film is composed of the bodily fluids proteins, polysaccharides and other components. This alteration of the surface characteristic allows bacteria to commence growth and colonization.

Using proper procedures, this initial biofilm should be removed with manual pre-cleaning, brushing accessible channels, followed by high level disinfection and thorough drying. The drying step must take place between cases as well as at the end of the day. If the biofilm is not completely removed, it will continue to grow and develop through repeated cycles of use and cleaning. Research has shown that under minimal growth conditions, 67% of adherent Pseudomonas aeruginosa strains remain metabolically active.

Natural biofilm forms on a surface continually bathed in fluid and exposed to microorganisms. The development of biofilm in endoscopes is thought to be associated with residual moisture left in channels that provide a medium for opportunistic pathogens originating from water sources. The gradual build up of material over repeated uses in reprocessed endoscopes forms with cyclical exposure to high level of microbes. Each procedure-reprocessing cycle involves scope exposure to hydrated phases as well as drying phases. These repeated cycles over time may facilitate biofilm formation consisting of layers of dried organic material with embedded microorganisms.

It is important to recognize and appreciate that flexible endoscopes are reportedly associated with more documented cases of healthcare-acquired infections than any other type of reusable medical device (Muscarella, 2006). Despite these findings, there have been no subsequent published reports directly linking an endoscope which has been reprocessed appropriately according to the current guidelines and not defective in design, to transmission of an infectious agent. Most published studies and reports relate to outbreaks, defective instruments or observed breaches in the reprocessing procedure. This fact alone should make us acutely aware that reprocessing an endoscope requires meticulous compliance with the standards of infection control as well as the specific reprocessing steps for each endoscope. It is essential to understand the capability of each automated reprocessor as it relates to the scopes and accessories that it will reprocess.


Drying each scope after each procedure will help to prevent biofilm formation.

Flexible endoscopes.

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