Impact of duodenoscope reprocessing factors on duodenoscope contamination: a retrospective observational study

Background: Despite adherence to reprocessing protocols, duodenoscopes frequently remain contaminated, highlighting significant knowledge gaps in reprocessing efficiency. Aim: To identify risk factors in duodenoscope reprocessing procedures affecting contamination rates. Methods: Cultures from Pentax ED34-i10T2 duodenoscopes collected between February 2022 and December 2023 were included. Contamination was determined by the presence of micro-organisms of gut or oral origin (MGO). Data on duodenoscope use, reprocessing lead times and personnel were retrieved from electronic medical records. Risk factors were derived from reprocessing guidelines and literature. These included a delay >30 min in initiating manual cleaning, manual cleaning duration of ≤5 min, drying time <90 min, personnel reprocessing frequency, and storage exceeding seven days. A logistic mixed-effects model evaluated these factors' impact on duodenoscope contamination. Findings: Out of 307 duodenoscope cultures, 58 (18.9%) were contaminated with MGO. Throughout the study period, the duodenoscopes underwent 1296 reprocessing cycles. Manual cleaning times of ≤5 min significantly increased contamination odds (adjusted odds ratio (aOR): 1.61; 95% confidence interval (CI): 1.10–2.34; P = 0.01). Increased usage of a duodenoscope was associated with reduced odds of contamination (aOR: 0.80; 95% CI: 0.64–0.995; P = 0.045). Other studied risks showed no clear association with contamination rates. Conclusion: Manual cleaning times of ≤5 min increased the odds of contamination with MGO. Delays in reprocessing initiation and incomplete drying, traditionally considered as risk factors, were not associated with an increased risk of contamination in this study. Future research should explore whether enhanced surveillance of reprocessing times can mitigate duodenoscope contamination.