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The bacterium Clostridioides difficile is the most frequent pathogen of nosocomial diarrhoeal diseases worldwide and is also increasingly found in the outpatient sector. According to studies, 20 to 30 cases of community-acquired infections occur per 100,000 inhabitants every year. The pathogen appears in the form of vegetative cells and in considerably resistant spore form. When selecting C. difficile-effective procedures for reprocessing flexible endoscopes, various aspects must be taken into account.
Risks from vegetative C. difficile cells
The vegetative Clostridioides difficile cells survive gastric acid only at pH values > 4. Therefore, patients with atrophic gastritis or patients taking proton pump inhibitors or H2 antagonists are considered to be more at risk, because in these cases C. difficile cells could enter the intestine.
Risks from C. difficile spores
The spore form of C. difficile, on the other hand, is very resistant: it remains infectious on inanimate surfaces for up to 5 months, survives gastric acid even at a pH value of 1 and germinates in the small intestine within 1 hour. The C. difficile spore can therefore pass the stomach easily even at a low pH value and germinate in the small intestine in a fairly short time and thus be converted into a form capable of reproduction.
Against this background, a differentiated picture emerges for the risk of infection through endoscopes:
- Colonoscopes
According to studies of patients with C. difficile infection, colonoscopes are often contaminated. However, the risk of infection through contaminated endoscopes appears to be comparatively low, since the spores in the colon only germinate with difficulty and the time for this is probably too short.
- Bronchoscopes/Gastroscopes/Duodenoscopes
The risk of contamination of bronchoscopes, gastroscopes and duodenoscopes seems low at first, but the risk of infection seems comparatively high. If pathogens enter the mouth/pharynx via the faecal-oral transmission path and enter the stomach via the endoscope, spores can survive gastric acid and have sufficient time to germinate in the small intestine on their long journey through the intestine.
Reprocessing of endoscopes
The spores of C. difficile have an enormous environmental resistance and can therefore only be inactivated using disinfection procedures with sporicidal efficacy.
Important for cleaning:
In the case of C. difficile, the already fundamental pre-cleaning of endoscopes is even more important. Mechanical removal of debris during pre-cleaning contributes to spore removal, especially in the narrow canals.
- Do not use agents such as aldehydes or peracetic acid in the cleaning process, as these fix organic components can "trap" bacterial spores, which are then difficult to reach by the subsequent disinfection.
- Replace contaminated cleaning solution immediately to avoid contamination of subsequent endoscopes with the spores. Clean/disinfect the reprocessing tank or basin before refilling.
Important during disinfection:
- Observe all process parameters for disinfection:
Exposure time: For some disinfectants, a sporicidal effect is indicated, which requires a considerably longer time than is usual in the RDG-E.
Temperature: Preparations based on glutaraldehyde are usually used at different temperatures than preparations based on peracetic acid. Here, the process parameters of the manufacturer must be taken into account.
Use procedural expertise as a basis
In order to ensure the greatest possible safety, users should only use programmes for which procedural reports are available in accordance with the recommendations of EN ISO 15883-4:2008 (Washer-disinfectors - Part 4: Requirements and test for washer-disinfectors employing chemical disinfection for thermolabile endoscopes) or the guideline for the validation of automated washer-disinfectors for the reprocessing of thermolabile endoscopes from 2011.
