A narrative review on current duodenoscope reprocessing techniques and novel developments

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.

Recommendations and guidelines for endoscope reprocessing: Current position statement of digestive endoscopic society of Taiwan

Reprocessing of gastrointestinal (GI) endoscopes and accessories is an essential part of patient safety and quality control in GI endoscopy centers. However, current endoscopic reprocessing guidelines or procedures are not adequate to ensure patient-safe endoscopy. Approximately 5.4 % of the clinically used duodenoscopes remain contaminated with high-concern microorganisms. Thus, the Digestive Endoscopy Society of Taiwan (DEST) sets standards for the reprocessing of GI endoscopes and accessories in endoscopy centers. DEST organized a task force working group using the guideline-revision process. These guidelines contain principles and instructions of step-by-step for endoscope reprocessing. The updated guidelines were established after a thorough review of the existing global and local guidelines, systematic reviews, and health technology assessments of clinical effectiveness. This guideline aims to provide detailed recommendations for endoscope reprocessing to ensure adequate quality control in endoscopy centers.

Cost-effectiveness Analysis of Single-Use Duodenoscope Applied to Endoscopic Retrograde Cholangiopancreatography

OBJECTIVES

Secondary infections due to transmission via the duodenoscope have been reported in up to 3% of endoscopic retrograde cholangiopancreatographies. The use of single-use duodenoscopes has been suggested. We investigate the cost-effectiveness of these duodenoscopes use in cholangiopancreatography.

MATERIALS AND METHODS

A cost-effectiveness analysis was implemented to compare the performance of cholangiopancreatographies with reusable duodenoscopes versus single-use duodenoscopes. Effectiveness was analyzed by calculating quality-adjusted life years (QALY) from the perspective of the National Health System. Possibility of crossover from single-use to reusable duodenoscopes was considered. A willingness-to-pay of €25,000/QALY was set, the incremental cost-effectiveness ratio (ICER) was calculated, and deterministic and probabilistic sensitivity analyses were performed.

RESULTS

Considering cholangiopancreatographies with single-use and reusable duodenoscopes at a cost of €2900 and €1333, respectively, and a 10% rate of single-use duodenoscopes, ICER was greater than €3,000,000/QALY. A lower single-use duodenoscope cost of €1211 resulted in an ICER of €23,583/QALY. When the unit cost of the single-use duodenoscope was €1211, a crossover rate of more than 9.5% made the use of the single-use duodenoscope inefficient.

CONCLUSIONS

Single-use duodenoscopes are cost-effective in a proportion of cholangiopancreatographies if its cost is reduced. Increased crossover rate makes single-use duodenoscope use not cost-effective.

Single-use accessories and endoscopes in the era of sustainability and climate change-A balancing act

Gastrointestinal (GI) endoscopy is among the highest waste generator in healthcare facilities. The major reasons include production of large-volume non-renewable waste, use of single-use devices, and reprocessing or decontamination processes. Single-use endoscopic accessories have gradually replaced reusable devices over last two decades contributing to the rising impact of GI endoscopy on ecosystem. Several reports of infection outbreaks with reusable duodenoscopes raised concerns regarding the efficacy and adherence to standard disinfection protocols. Even the enhanced reprocessing techniques like double high-level disinfection have not been found to be the perfect ways for decontamination of duodenoscopes and therefore, paved the way for the development of single-use duodenoscopes. However, the use of single-use endoscopes is likely to amplify the net waste generated and carbon footprint of any endoscopy unit. Moreover, single-use devices challenge one of the major pillars of sustainability, that is, "reuse." In the era of climate change, a balanced approach is required taking into consideration patient safety as well as financial and environmental implications. The possible solutions to provide optimum care while addressing the impact on climate include selective use of disposable duodenoscopes and careful selection of accessories during a case. Other options include use of disposable endcaps and development of effective high-level disinfection techniques. The collaboration between the healthcare professionals and the manufacturers is paramount for the development of environmental friendly devices with low carbon footprint.

Global prospective case series of ERCPs using a single-use duodenoscope

BACKGROUND

 The first commercialized single-use duodenoscope was cleared by the US Food and Drug Administration in December 2019. Data regarding endoscopic retrograde cholangiopancreatography (ERCP) using a single-use duodenoscope are needed on a broader range of cases conducted by endoscopists with varying levels of experience in a wide range of geographic areas.

METHODS

 61 endoscopists at 22 academic centers in 11 countries performed ERCP procedures in adult patients aged ≥ 18. Outcomes included ERCP completion for the intended indication, rate of crossover to a reusable endoscope, device performance ratings, and serious adverse events (SAEs).

RESULTS

 Among 551 patients, 236 (42.8 %) were aged > 65, 281 (51.0 %) were men, and 256 (46.5 %) had their procedure as an inpatient. ERCPs included 196 (35.6 %) with American Society for Gastrointestinal Endoscopy complexity of grades 3-4. A total of 529 ERCPs (96.0 %) were completed: 503 (91.3 %) using only the single-use duodenoscope, and 26 (4.7 %) with crossover to a reusable endoscope. There were 22 ERCPs (4.0 %) that were not completed, of which 11 (2.0 %) included a crossover and 11 (2.0 %) were aborted cases (no crossover). Median ERCP completion time was 24.0 minutes. Median overall satisfaction with the single-use duodenoscope was 8.0 (scale of 1 to 10 [best]). SAEs were reported in 43 patients (7.8 %), including 17 (3.1 %) who developed post-ERCP pancreatitis.

CONCLUSIONS

 In academic medical centers over a wide geographic distribution, endoscopists with varying levels of experience using the first marketed single-use duodenoscope had good ERCP procedural success and reported high performance ratings for this device.

Disinfection and sterilization: New technologies

BACKGROUND

Adherence to professional guidelines and/or manufacturer's instructions for use regarding proper disinfection and sterilization of medical devices is crucial to preventing cross transmission of pathogens between patients. Emerging pathogens (e.g., Candida auris) and complex medical devices provide new challenges.

METHODS

A search for published English articles on new disinfection and sterilization technologies was conducted by Google, Google scholar and PubMed.

RESULTS

Several new disinfection methods or products (e.g., electrostatic spraying, new sporicides, colorized disinfectants, "no touch" room decontamination, continuous room decontamination) and sterilization technologies (e.g., new sterilization technology for endoscopes) were identified.

CONCLUSIONS

These technologies should reduce patient risk.

New Hydrogels Nanocomposites Based on Chitosan, 2-Formylphenylboronic Acid, and ZnO Nanoparticles as Promising Disinfectants for Duodenoscopes Reprocessing

New hydrogels nanocomposites, based on iminoboronate hydrogels and ZnO nanoparticles (ZnO-NPs), were obtained and characterised in order to develop a new class of disinfectants able to fight the nosocomial infections produced by duodenoscopes investigation procedures. The formation of the imine linkages between chitosan and the aldehyde was demonstrated using NMR and FTIR spectroscopy, while the supramolecular architecture of the developed systems was evaluated via wide-angle X-ray diffraction and polarised optical microscopy. The morphological characterisation of the systems via scanning electron microscopy revealed the highly porous structure of the materials, in which no ZnO agglomeration could be observed, indicating the very fine and homogenous encapsulation of the nanoparticles into the hydrogels. The newly synthetised hydrogels nanocomposites was proven to have synergistic antimicrobial properties, being very efficient as disinfectants against reference strains as: Enterococcus faecalis, Klebsiella pneumoniae, and Candida albicans.

Mechanical deformation of elastomer medical devices can enable microbial surface colonization

Elastomers such as silicone are common in medical devices (catheters, prosthetic implants, endoscopes), but they remain prone to microbial colonization and biofilm infections. For the first time, our work shows that rates of microbial surface attachment to polydimethylsiloxane (PDMS) silicone can be significantly affected by mechanical deformation. For a section of bent commercial catheter tubing, bacteria (P. aeruginosa) show a strong preference for the 'convex' side compared to the 'concave' side, by a factor of 4.2. Further testing of cast PDMS materials in bending only showed a significant difference for samples that were manually wiped (damaged) beforehand (1.75 × 10⁴ and 6.02 × 10³ cells/mm² on the convex and concave sides, respectively). We demonstrate that surface microcracks in elastomers are opened under tensile stress (convex bending) to become 'activated' as sites for microbial colonization. This work demonstrates that the high elastic limit of elastomers enables these microcracks to reversibly open and close, as 'dynamic defects'. Commercial catheters have relatively high surface roughness inherent to manufacturing, but we show that even manual wiping of newly-cast PDMS is sufficient to generate surface microcracks. We consider the implication for medical devices that feature sustained, surgical, or cyclic deformation, in which localized tensile conditions may expose these surface defects to opportunistic microbes. As a result, our work showcases serious potential problems in the widespread usage and development of elastomers in medical devices.

Endoscope reprocessing: Retrospective analysis of 90,311 samples

Background and study aims The contamination level of ready-to-use endoscopes published in the literature varies from 0.4 % to 49.0 %. Unfortunately, the comparison and the interpretation of these results are quite impossible, given the limited number of samples and sites included and the differences observed between sampling, culturing methods, and interpretation criteria. Methods The objective of this retrospective study was to analyze the results of 90,311 endoscope samples collected between 2004 and 2021 in 490 private or public hospitals in France. Results Through the full test period, the mean ratio of endoscopes at the action level was 12.6 % (19.5 % including alert level). Of the endoscopy units, 23.0 % had a ratio of compliant endoscopes ≤ 70.0 %. The overall microbial quality of gastroscopes, duodenoscopes, and colonoscopes is improving year by year, whereas an opposite trend is observed for ultrasound endoscopes and bronchoscopes. In 2021, following French guidelines, 13.0 % of the endoscopes should have been quarantined and 8.1 % were at the alert level, meaning that the contamination level of 21.1 % of the endoscopes exceeded what was defined as a maximum acceptable value. Conclusions This study demonstrates that additional efforts, including implementation of microbial surveillance strategies using a standardized sampling method and periodic observational audits, must be made to improve the overall microbiological quality of endoscopes and reduce the risk associated with their use.

Effectiveness of adenosine triphosphate to monitor manual cleaning and disinfection efficacy of flexible endoscopes in Hong Kong

Background and Aim

Adenosine triphosphate (ATP) bioluminescence assay is widely adopted in the West to allow rapid evaluation of endoscopes for bacteriologic/biologic residue, but this practice is rarely adopted in Asia. In this continuous quality improvement program, we evaluated the utility of ATP in bacteriologic surveillance on endoscope reprocessing.

Methods

A total of 456 samples (304 ATP samples and 152 culture samples) of 38 flexible endoscopes were assessed after routine clinical use in a private hospital in Hong Kong. Endoscopes were assessed with an ATP system and bacterial cultures at different time points during the reprocessing.

Results

After pre-cleaning, the ATP values ranged from 228 to 65 163 relative light units (RLU) through all endoscope types. After manual cleaning, ATP values were decreased to 7-81 RLU (median, 19 RLU) for endoscope surface and 3-671 RLU (median, 12 RLU) for channel rinsate. There was a significant reduction in ATP levels between pre-cleaning and after manual cleaning. One of the 38 (2.6%) endoscopes (a duodenoscope) had an ATP value of 671 RLU from channel rinsate, which exceeded the benchmark for cleanliness of >200 RLU, and was sent back for re-cleaning. All endoscopes cultured no bacteria after high-level disinfection (HLD) by automated endoscope reprocessor (AER) and storage up to 24 h. ATP values were <200 RLU for all endoscopes after HLD and storage.

Conclusions

Adenosine triphosphate bioluminescence assay offers a rapid, practical, and cost-effective alternative for detection of endoscope microbial residue as well as a routine monitoring tool for endoscope cleanliness in the clinical setting.