Assessment of postmanual cleaning adenosine triphosphate tests to prevent the use of contaminated duodenoscopes and linear echoendoscopes: the DETECT study

Contaminated duodenoscopes in ERCP: sensitivity of detection and risk of underdetection

BACKGROUND AND AIMS

Periodic duodenoscope cultures are essential to timely detect contamination, but their sensitivity remains unknown. This study aims to determine the sensitivity of duodenoscope cultures and to estimate the prevalence of contaminated duodenoscope use.

METHODS

We combined duodenoscope microbiologic surveillance data from March 2015 to June 2022 with usage data to evaluate patient exposure to duodenoscopes contaminated with microorganisms of gut or oral origin (MGO). We identified duodenoscopes with repeated species-level contamination within a year and used molecular typing to confirm genetic relatedness. Genetically related microorganisms over multiple duodenoscope cultures of a single duodenoscope indicated a period of sustained contamination, and a cluster was defined as overlapping periods of sustained contamination between different duodenoscopes. If microorganisms were not available for molecular analysis, we marked the period as unconfirmed. A sample was defined as false negative if it did not show the target microorganism(s) in a period of sustained contamination. We used 3 scenarios to hypothesize about contaminated use and culture sensitivity.

RESULTS

We included 556 duodenoscope cultures with 185 (33.3%) contaminated with MGO. The total usage of duodenoscopes was 5226. We identified 1 period of sustained contamination, 6 unconfirmed periods, and 2 clusters. Depending on our scenario assumptions, the percentage of contaminated use varied from 12.3% to 23.7% and culture sensitivity ranged from 82.2% to 98.9%.

CONCLUSIONS

Limited sensitivity of duodenoscope cultures leads to improper clearance of duodenoscopes for clinical use, increasing risks of outbreaks. The applicability of a single culture to end a duodenoscope's quarantine should be re-evaluated.

No relation between adenosine triphosphate after manual cleaning and presence of microorganisms on endoscopes after automated high-level disinfection

Background and study aims  Adenosine triphosphate (ATP) tests are increasingly used to detect biological material; however, their reliability to detect bacterial contamination in endoscopes is not proven. We investigated the predictive value of ATP tests after manual cleaning for presence or absence of microorganisms as shown by culture after automated high-level disinfection (HLD) in duodenoscopes and linear echoendoscopes (DLEs). Patients and methods  After manual cleaning, ATP tests were performed on swab samples taken from the detachable cap and forceps elevator, and on flush samples of the DLE working channels. These results were compared to the growth of any microorganisms in cultures acquired after automated HLD. ATP tests with > 200 relative light units (RLU) were considered positive. Receiver operator characteristic (ROC) curves were used to compare the RLU levels with microbial presence in cultures. Results  In total, 903 procedures were performed involving 26 distinct DLEs. Depending on sample site, 20.8 % (cap) to 63.8 % (channel brush) of the ATP negative samples were accompanied by positive post-HLD cultures. 54.4 % of the cap samples with a positive culture (growth of any kind of microorganism) and 91.8 % of the channel samples with a positive culture had a negative ATP test after manual cleaning. ROC curves per sample site, DLE type and microorganism type all had area under the curves below 0.6. Conclusions  In our study, ATP tests performed after manual cleaning could not predict presence or absence of microorganisms after automated HLD as shown by culture. More than half of the positive cultures were preceded by a negative ATP test.