Unveiling 8 years of duodenoscope contamination: insights from a retrospective analysis in a large tertiary care hospital

Contaminated duodenoscopes caused several hospital outbreaks. Despite efforts to reduce contamination rates, 15% of patient-ready duodenoscopes are still contaminated with gastrointestinal microorganisms. This study aimed to provide an overview of duodenoscope contamination over time, identify risk factors and study the effects of implemented interventions.Duodenoscope culture sets between March 2015 and June 2022 at a Dutch tertiary care centre were analysed. Contamination was defined as (1) the presence of microorganisms of oral or gastrointestinal origin (MGO) or (2) any other microorganism with ≥20 colony-forming units/20 mL (AM20). A logistic mixed effects model was used to identify risk factors and assess the effect of interventions, such as using duodenoscopes with disposable caps, replacing automated endoscope reprocessors (AER) and conducting audits in the endoscopy department.A total of 404 culture sets were analysed. The yearly contamination rate with MGO showed great variation, ranging from 14.3% to 47.5%. Contamination with AM20 increased up to 94.7% by 2022. For both MGO and AM20, the biopsy and suction channels were the most frequently contaminated duodenoscope components. The studied interventions, including audits, AER replacement and implementation of duodenoscopes with disposable caps, did not show a clear association with contamination rates.Duodenoscope contamination remains a significant problem, with high contamination rates despite several interventions. Reprocessing the biopsy and suction channels is especially challenging. Changes in the design of reusable duodenoscopes, such as enabling sterilisation or easily replaceable channels, are necessary to facilitate effective duodenoscope reprocessing and to eliminate the risk of duodenoscope-associated infections.