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 degrees C, followed by a 5-min cleaning step at 45 degrees C (with an enzymatic cleaner, 0.5 %), followed by a 1-min interim rinse from 45 degrees C to 55 degrees C. The disinfection process consisted of a 1-min prerinse at 20 degrees C, followed by a 5-min disinfection step at 55 degrees C (with a glutaraldehyde-based disinfectant, 1 %), followed by two final rinses of 1 min each at 55 degrees 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 > or = 4.6 (n = 6); the disinfection process revealed a mean reduction factor of > or = 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 log (10) steps (n = 12) and in the AdaptaScope by 9.3 +/- 0.4 log (10) 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.