Evaluation of the Effectiveness of an Enzymatic Cleaner and Glutaraldehyde-Based Disinfectant for Chemothermal Processing of Flexible Endoscopes in Washer-Disinfectors in Accordance with prEN ISO 15 883

Background and Study Aims: This study evaluated the effectiveness of the cleaning process, the disinfection process, and a combination of the two in accordance with the new international standard, prEN ISO 15 883.
Materials and Methods: The cleaning process consisted of a 1-min prerinse at 20 °C, followed by a 5-min cleaning step at 45 °C (with an enzymatic cleaner, 0.5 %), followed by a 1-min interim rinse from 45 °C to 55 °C. The disinfection process consisted of a 1-min prerinse at 20 °C, followed by a 5-min disinfection step at 55 °C (with a glutaraldehyde-based disinfectant, 1 %), followed by two final rinses of 1 min each at 55 °C. Transparent test pieces were contaminated with a mixture of blood and Enterococcus faecium, and were assessed for visible cleanliness and microbial load.
Results: Cleaning alone, disinfection alone, and the combination of the two always led to visible cleanliness of all test pieces. The cleaning process revealed a mean reduction factor of ≥ 4.6 (n = 6); the disinfection process revealed a mean reduction factor of ≥ 9.0 (n = 6), and the combination of the two was found to reduce the test organism in the WD440 by 9.0 ± 0.2 log₁₀ steps (n = 12) and in the AdaptaScope by 9.3 ± 0.4 log₁₀ steps (n = 5).
Conclusions: Overall, the entire process was found to be very effective and compatible for reprocessing flexible endoscopes in washer-disinfectors. No visible residual blood was found, despite the use of glutaraldehyde in the disinfection phase. These findings once again emphasize the importance of effective cleaning for the overall results when reprocessing flexible endoscopes.

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