Does sterile reprocessing of thermolabile flexible endoscopes in endoscope washer-disinfectors increase the safety margin?



Letter to the Editor from:
Dr. Birgit Kampf*, OLYMPUS EUROPA SE & CO. KG, Amsinckstraße 63, 20097 Hamburg, Germany; Prof. Dr. rer. nat. Heike Martiny, TechnischeHygiene, Weygerweg 20, 12249 Berlin, Germany Dr. Lionel Pineau, Eurofins Biotech Germande ,163 Avenue du Luminy-case 927, Marseille Cedex 09/13288, France

Patient infections related to endoscopic procedures have been repeatedly reported in recent years. This has led to ongoing debates whether the current practice of cleaning and disinfection of semi-critical thermolabile endoscopes is sufficient for eliminating the high microbial load after use of the devices [6, 7]. Consequently, it has been discussed if a terminal sterilization on a routine basis for all semi-critical thermolabile endoscopes after their reprocessing in an endoscope washer-disinfector (EWD) provides a higher safety margin [8].

Within this framework, the U.S. Food and Drug Administration (FDA) proposed terminal sterilization of duodenoscopes after cleaning and disinfection or double High-Level Disinfection (HLD), among others [9]. Meanwhile first results are published, showing that neither double HLD, nor sterilization with ethylene oxide (ETO) always successfully eliminate all microorganisms/ remove multi-resistant pathogens [10–14].

Most flexible endoscopes are classified as semi-critical devices according to the Spaulding classification of medical devices, as they come into contact with intact mucous membranes and do not ordinarily penetrate sterile tissue. Consequently, they require cleaning and disinfection with disinfectants claiming to have bactericidal, fungicidal, mycobactericidal, and virucidal activity by application of relevant EN standards (which reflects the process of HLD in some countries) [1].

The common reprocessing procedure for most flexible endoscopes consists of precleaning and manual cleaning, followed by automated cleaning and disinfection in EWD complying with the relevant standard series of EN ISO 15883 [3–5]. To remove the disinfectant, rinsing with water of defined quality according to EN ISO 15883- 4 and volume is integral part of the EWD program. Drying with air of defined quality according to EN ISO 15883-4 takes place either within the EWD, manually by using compressed filtered air (see Figure 1), or in a storage cabinet (see EN 16442) [17].

The quality of water and air used after disinfection is important to avoid recontamination with potentially pathogens (e.g. Pseudomonas spp., Legionella spp., atypical mycobacteria) and thus to maintain the microbial status of “disinfection”.

According to EN ISO 15883-4, the term “disinfection” is defined as the reduction of microorganisms present on a product to a level previously specified as appropriate for its intended further handling or use. ...


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