A search strategy for detecting duodenoscope-associated infections: a retrospective observational study

BACKGROUND

Duodenoscope-associated infections (DAIs) are exogenous infections resulting from the use of contaminated duodenoscopes. Though numerous outbreaks of DAI have involved multidrug-resistant micro-organisms (MDROs), outbreaks involving non-MDROs are also likely to occur. Detection challenges arise as these infections often resolve before culture or because causative strains are not retained for comparison with duodenoscope strains.

AIM

To identify and analyse DAIs spanning a seven-year period in a tertiary care medical centre.

METHODS

This was a retrospective observational study. Duodenoscope cultures positive for gastrointestinal flora between March 2015 and September 2022 were paired with duodenoscope usage data to identify patients exposed to contaminated duodenoscopes. Analysis encompassed patients treated after a positive duodenoscope culture and those treated within the interval from a negative to a positive culture. Patient identification numbers were cross-referenced with a clinical culture database to identify patients developing infections with matching micro-organisms within one year of their procedure. A 'pair' was established upon a species-level match between duodenoscope and patient cultures. Pairs were further analysed via antibiogram comparison, and by whole-genome sequencing (WGS) to determine genetic relatedness.

FINDINGS

Sixty-eight pairs were identified; of these, 21 exhibited matching antibiograms which underwent WGS, uncovering two genetically closely related pairs categorized as DAIs. Infection onset occurred up to two months post procedure. Both causative agents were non-MDROs.

CONCLUSION

This study provides crucial insights into DAIs caused by non-MDROs and it highlights the challenge of DAI recognition in daily practice. Importantly, the delayed manifestation of the described DAIs suggests a current underestimation of DAI risk.

Higher yield in duodenoscope cultures collected with addition of neutralizing agent

AIM

Microbiological cultures are the gold standard in the monitoring of duodenoscope reprocessing. However, many different sampling and culturing techniques are used, making it difficult to compare results. The latest Centers for Disease Control and Prevention protocol advises the use of a neutralizer to deactivate any remaining disinfectants in the samples. This study compared culturing results of duodenoscope samples collected with and without addition of a neutralizer.

METHODS

Six duodenoscopes were soiled with gut bacteria in a non-clinical experimental setting and reprocessed afterwards. Samples of the tip and working channel were collected immediately after decontamination or after drying. Dey-Engley (DE) broth was added as a neutralizer to the samples of four duodenoscopes; samples for the other two duodenoscopes were collected without the addition of DE broth.

RESULTS

Post-decontamination cultures were significantly more likely to be positive for growth of the applied micro-organisms in the group of samples with DE broth (88.1% vs 20.2%; P<0.0001). Post-drying samples were significantly more likely to be positive in the group of samples without DE broth (75.7% vs 33.4%; P<0.001).

CONCLUSION

The addition of DE broth to samples collected from wet duodenoscopes increases the yield of those cultures. Remaining disinfectants in wet duodenoscopes can lead to false-negative results. This can be overcome by adding a neutralizer, such as DE broth, to the samples. The higher yield after drying in the group without neutralizer could be due to biofilm formation in these two duodenoscopes, but this was not investigated. Standardization of the sampling method can help to compare both clinical and study results regarding duodenoscope contamination.

Microbiological surveillance post-reprocessing of flexible endoscopes used in digestive endoscopy: a national study

INTRODUCTION

Microbiological surveillance of endoscopes is a safety measure for verifying the quality of reprocessing procedures and identifying contaminated devices, but duodenoscope-related outbreaks are still reported.

AIM

To assess the effectiveness of duodenoscope reprocessing procedures in Italy.

METHODS

Between December 2019 and April 2020, data obtained from microbiological surveillance post-reprocessing in 15 Italian endoscopy units were collected. Sampling was carried out after reprocessing or during storage in a cabinet. In keeping with international guidelines and the Italian position paper, the micro-organisms were classified as high-concern organisms (HCOs) and low-concern organisms (LCOs).

FINDINGS

In total, 144 samples were collected from 51 duodenoscopes. Of these, 36.81% were contaminated: 22.92% were contaminated with HCOs and 13.89% were contaminated with LCOs [2.08% with an LCO load of 11-100 colony-forming units (CFU)/device and 0.69% with an LCO load of >100 CFU/device]. The contamination rate was 27.5% in samples collected after reprocessing, 40% in samples collected during storage in a cabinet that was compliant with EN 16442:2015 (C-I), and 100% in samples collected during storage in a cabinet that was not compliant with EN 16442:2015 (NC-I). The respective HCO rates were 15.00%, 27.27% and 66.67%. Correlation between LCO contamination and storage time was demonstrated (Spearman's rho=0.3701; P=0.0026). The Olympus duodenoscope TJFQ180V demonstrated the lowest rate of contamination (29.82%), although the contamination rate was 100% for duodenoscopes stored in an NC-I cabinet.

CONCLUSION

Microbiological surveillance, along with strict adherence to reprocessing protocols, may help to detect endoscope contamination at an early stage, and reduce the risk of duodenoscope-associated infections.

Single Use (disposable) Duodenoscope: Recent Development and Future

Unlike simple forward-viewing endoscopes such as gastroscope or colonoscope, duodenoscope houses much more complex design to fulfil its function. This design differences leave duodenoscopes more prone to contamination from inadequate disinfection process and potential dissemination of pathogens. Recent reports on dissemination of infection through the duodenoscope mandated an overhaul of duodenoscope utilization including development of a disposable duodenoscope. This article reviews the current state of disposable duodenoscope development, including reported early efficacy as well as its future direction and utilization.

Flexible gastrointestinal endoscope processing challenges, current issues and future perspectives

BACKGROUND

At present, the most frequent method for processing flexible gastrointestinal (GI) endoscopes is cleaning followed by high-level disinfection as terminal sterilization is often not practicable. Post-processing monitoring studies consistently show high levels of positive cultures remaining on endoscopes, which can lead to patient infection and even fatality. The processing deficiency is attributed to the complex design of endoscopes, incomplete cleaning, formation of biofilms and lack of margin of safety with high-level disinfection.

OBJECTIVE

To demonstrate that flexible GI endoscopes can be practicably terminally sterilized.

METHODS

An endoscope sterilization cycle was developed in a vaporized hydrogen peroxide sterilization system. The cycle was used to study the sterilization of flexible GI endoscopes which included colonoscopes and duodenoscope and material compatibility for both original flexible GI endoscopes and those experimentally modified endoscopes using compatible materials.

RESULTS

Testing demonstrated that the vaporized hydrogen peroxide can sterilize flexible GI endoscopes (colonoscopes, duodenoscope) with a sterility assurance level of 10^-6. Additionally, no recoverable survivors were detected when devices were artificially soiled with hard water and serum. Material compatibility test results demonstrated that replacing molybdenum disulphide lubricant with a graphite-based inert lubricant can make them compatible with vaporized hydrogen peroxide sterilizers.

CONCLUSION

Flexible GI endoscopes can be practicably terminally sterilized using vaporized hydrogen peroxide sterilization technologies if their materials are revised to become compatible.

Duodenoscope as a Vector for Transmission

Elevator-based endoscope-related infections from patient cross-contamination is a multifactorial problem related to device design, maintenance, and function, with additional risk incurred from a high-level disinfection process that lacks quality controls. This article reviews the historical context for these outbreaks, technical aspects of scope design contributing to this risk, and innovations in endoscope technology that have the potential to overcome these shortcomings. Also reviewed are interim solutions and the data that support use of some of these interventions. Still needed are a validated manufacturer-recommended schedule for routine duodenoscope and echoendoscope maintenance with reprocessing protocols that can be implemented in endoscopy units.

Recent Actions by the US Food and Drug Administration: Reducing the Risk of Infection from Reprocessed Duodenoscopes

In addition to technological advancements, engagement and collaboration among the wider community of stakeholders will be beneficial toward reducing the risk of infection from reprocessed duodenoscopes. Such a community can raise awareness of the importance of duodenoscope cleaning, work to improve reprocessing training, identify the most pressing unanswered questions that merit further research, and develop tools that can be used by health care facilities to improve the quality of reprocessing at their sites. The Food and Drug Administration looks forward to working with the community to further reduce the risk of infections from reprocessed duodenoscopes.

Quality Systems Approach for Endoscope Reprocessing: You Don't Know What You Don't Know!

Several factors affect the efficacy of endoscope reprocessing, including human factors, inadequate cleaning, simethicone residuals, moisture in channels during storage, and biofilm or buildup biofilm formation. These factors all contribute to contamination of patient-ready endoscopes that may contribute to transmission of microorganisms resulting in infection and/or colonization. This article reviews monitoring as part of a quality management system that includes manual cleaning, dry storage, and culture to detect endoscope contamination. The published data for rapid tests that detect organic residuals and adenosine triphosphate to monitor manual cleaning are reviewed.

Performance characteristics and optimal cut-off value of triple adenylate nucleotides test versus adenosine triphosphate test as point-of-care testing for predicting inadequacy of duodenoscope reprocessing

BACKGROUND

Adenosine triphosphate (ATP) test based on one nucleotide has been applied as point-of-care testing (POCT) for bacterial contamination in the medical and food industries. Hypothetically, testing three adenylate nucleotides (A3) may provide better detection of duodenoscope bacterial contamination than ATP test.

AIM

To evaluate performance characteristics and optimal cut-off value of A3 and ATP tests in predicting bacterial contamination of duodenoscopes.

METHODS

Four hundred duodenoscope samples obtained after 100 endoscopic retrograde cholangiopancreatography procedures were randomized into group A (A3 test) or B (ATP test). Samples were collected from the elevator at the four-step cleaning process of duodenoscope. We defined the new cut-off value of the test for reaching 100% negative predictive value (NPV) from our receiver operating characteristic (ROC).

FINDINGS

Using the cultures from the four-step cleaning process as the reference, the areas under ROC (AUROC) were 0.83 and 0.84 for group A (N = 200) and group B (N = 200), respectively. Using the cultures from post-high-level disinfection (HLD) as the reference, the AUROC were 0.35 and 0.74 for group A (N = 50) and group B (N = 50), respectively. We investigated ATP as a POCT after HLD with a new cut-off value of 40 RLU. However, this threshold did not allow detection of low numbers of bacteria.

CONCLUSION

A3 and ATP tests provide good performances in predicting bacterial contamination of duodenoscopes for the four-step cleaning process. The ATP <40 RLU is helpful as a POCT after HLD; however, the limitation of this cut-off value is its inability to detect low numbers of bacteria.

Rate and impact of duodenoscope contamination: A systematic review and meta-analysis

BACKGROUND

Multiple infection outbreaks have been linked to contaminated duodenoscopes worldwide. However, the contamination rate of patient-ready duodenoscopes varies highly amongst published studies testing this subject. We aimed to estimate the contamination rate of reprocessed patient-ready duodenoscopes for endoscopic retrograde cholangio-pancreatography (ERCP) based on currently available data.

METHODS

We searched the PubMed and Embase databases from January 1, 2010 until March 10, 2020, for citations investigating contamination rates of reprocessed patient-ready duodenoscopes. Studies not assessing other types of endoscopes than duodenoscopes were excluded from the analysis. Study eligibility and data extraction was evaluated by three reviewers independently. A random-effects model (REM) based on the proportion distribution was used to calculate the pooled total contamination rate of reprocessed patient-ready duodenoscopes. Subgroup analyses were carried out to assess contamination rates when using different reprocessing methods by comparing single high-level disinfection (HLD) with double HLD and ethylene oxide (EtO) gas sterilization. Additionally, we investigated the contamination rate between studies conducted following an outbreak compared to non-outbreak-initiated studies.

FINDINGS

We identified 15 studies that fulfilled the inclusion, which included 925 contaminated duodenoscopes from 13,112 samples. The calculated total weighted contamination rate was 15.25% ± 0.018 (95% confidence interval [Cl]: 11.74% - 18.75%). The contamination rate after only using HLD was 16.14% ± 0.019 (95% Cl: 12.43% - 19.85%) and after using either dHLD or EtO the contamination rate decreased to 9.20% ± 0.025 (95% Cl: 4.30% - 14.10%). Studies conducted following an outbreak (n=4) showed a 5.72% ± 0.034 (95% Cl: 0.00% - 12.43%) contamination rate, and non-outbreak-initiated studies (n=11) revealed a contamination rate of 21.50% ± 0.031 (95% Cl: 15.35% - 27.64%).

INTERPRETATION

This is the first meta-analysis to estimate the contamination rate of patient-ready duodenoscopes used for ERCP. Based on the available literature, our analysis demonstrates that there is a 15.25% contamination rate of reprocessed patient-ready duodenoscopes. Additionally, the analysis indicates that dHLD and EtO reprocessing methods are superior to single HLD but still not efficient in regards to cleaning the duodenoscopes properly. Furthermore, studies conducted following an outbreak did not entail a higher contamination rate compared to non-outbreak-initiated studies.

FUNDING

The authors received no financial support for the research, authorship, and/or publication of this article.

Infection control in ERCP using a duodenoscope with a disposable cap (ICECAP): rationale for and design of a randomized controlled trial

BACKGROUND

Endoscopic retrograde cholangio-pancreatography (ERCP) is commonly performed in the management of pancreatic and biliary disease. Duodenoscopes are specialized endoscopes used to perform ERCP, and inherent to their design, a high rate of persistent bacterial contamination exists even after automated reprocessing and disinfection. Consequently, in recent years, ERCP has been associated with infection transmission, leading to several fatal patient outbreaks. Due to increasing fears over widespread future duodenoscope-related outbreaks, regulatory bodies have called for alterations in the design of duodenoscopes. A duodenoscope has recently been developed that employs a disposable cap. This novel design theoretically eliminates the mechanism behind persistent bacterial contamination and infection transmission. However, there are no data demonstrating persistent bacterial contamination rates, technical success rates, or clinical outcomes associated with these duodenoscopes.

METHODS

A parallel arm randomized controlled trial will be performed for which 520 patients will be recruited. The study population will consist of consecutive patients undergoing ERCP procedures for any indication at a high-volume tertiary care centre in Calgary, Alberta, Canada. Patients will be randomized to an intervention group, that will undergo ERCP with a novel duodenoscope with disposable cap, or to a control group who will undergo ERCP with a traditional duodenoscope. Co-primary outcomes will include persistent bacterial contamination rates (post automated reprocessing) and ERCP technical success rates. Secondary outcomes include clinical success rates, overall and specific early and late adverse event rates, 30-day mortality and healthcare utilization rates, procedure and reprocessing times, and ease of device use.

DISCUSSION

The ICECAP trial will answer important questions regarding the use of a novel duodenoscope with disposable cap. Specifically, persistent bacterial contamination, technical performance, and relevant clinical outcomes will be assessed. Given the mortality and morbidity burden associated with ERCP-related infectious outbreaks, the results of this study have the capacity to be impactful at an international level.

TRIAL REGISTRATION

This trial was registered on clinicaltrials.gov (NCT04040504) on July 31, 2019.

Duodenoscope-Associated Infections: Update on an Emerging Problem

The duodenoscope is among the most complex medical instruments that undergo disinfection between patients. Transmission of infection by contaminated scopes has remained a challenge since its inception. Notable risk factors for pathogen transmission include non-adherence to disinfection guidelines, encouragement of biofilm deposition due to complex design and surface defects and contaminated automated endoscope reprocessors. The most common infections following endoscopy are endogenous infections involving the patient's own gut flora. Exogenous infections, on the other hand, are associated with contaminated scopes and can theoretically be prevented by effective reprocessing. Pseudomonas aeruginosa is currently the most common organism isolated from contaminated endoscopes. Of note, reports of multidrug-resistant duodenoscopy-associated outbreaks have surfaced recently, many of which occurred despite adequate reprocessing. The FDA and CDC currently recommend comprehensive cleaning followed with at least high-level disinfection for reprocessing of flexible GI endoscopes. Reports of duodenoscope-related outbreaks despite compliance with established guidelines have prompted professional and government bodies to revisit existing guidelines and offer supplementary recommendations for duodenoscope processing. For the purposes of this review, we identified reports of duodenoscope-associated infections from 2000 till date. For each outbreak, we noted the organisms isolated, the number of cases reported, any possible explanations of contamination, and the measures undertaken to end each outbreak. We have also attempted to present an overview of recent developments in this rapidly evolving field.

Use of adenosine triphosphate to audit reprocessing of flexible endoscopes with an elevator mechanism

BACKGROUND

There have been reported outbreaks of carbapenem-resistant Enterobacteriaceae infections linked to endoscopes with elevator mechanisms. Adenosine triphosphate (ATP) testing has been used as a marker for bioburden and monitoring manual cleaning for flexible endoscopes with and without an elevator mechanism. The objective of this study was to determine whether routine ATP testing could identify areas of improvement in cleaning of endoscopes with an elevator mechanism.

METHODS

ATP testing after manual cleaning of TJF-Q180V duodenoscopes and GF-UCT180 linear echoendoscopes (Olympus America Inc, Center Valley, PA) was implemented. Samples were tested from the distal end, the elevator mechanism, and water flushed through the lumen of the biopsy channel. Data were recorded and compared by time point, test point, and reprocessing technician.

RESULTS

Overall failure rate was 6.99% (295 out of 4,219). The highest percentage of failed ATP tests (17.05%) was reported in the first quarter of routine testing, with an overall decrease in rates over time. The elevator mechanism and working channel lumen had higher failure rates than the distal end. Quality of manual cleaning between reprocessing technicians showed variation.

CONCLUSION

ATP testing is effective in identifying residual organic material and improving quality of manual cleaning of endoscopes with an elevator mechanism. Cleaning efficacy is influenced by reprocessing technicians and location tested on the endoscope. Close attention to the working channel and elevator mechanism during manual cleaning is warranted.

New Developments in the Prevention of Gastrointestinal Scope-Related Infections

Gastrointestinal endoscopes are used for diagnostic and therapeutic purposes and are the most common medical device implicated in health care-associated outbreaks. Infections can be divided into endogenous or exogenous. Exogenous infections were associated with lapses in reprocessing. Recent outbreaks have occurred despite compliance with reprocessing guidelines and highlight the challenges with clearance of all organisms from the duodenoscopes and the potential role of biofilms in hindering adequate reprocessing. This review provides an overview of recent developments and the current understanding of the key contributing factors related to gastrointestinal endoscope-related infections and current approaches to identify and prevent these complications.

Forward-viewing endoscope for ERCP in patients with Billroth II gastrectomy: a systematic review and meta-analysis

BACKGROUND

The forward-viewing endoscope has been increasingly used to perform endoscopic retrograde cholangiopancreatography (ERCP) in patients who underwent Billroth II gastrectomy. This study intended to assess efficacy and safety of the forward-viewing endoscope for ERCP in Billroth II gastrectomy patients compared with conventional side-viewing endoscope using a systematic review and meta-analysis.

METHODS

A systematic review was conducted for studies that evaluated the outcomes of ERCP for patients with Billroth II gastrectomy. Random-effect model meta-analyses with subgroup analyses were conducted. The methodological quality of the included publications was evaluated using the risk of bias assessment tool for non-randomized studies. The publication bias was assessed.

RESULTS

In total, 25 studies (1 randomized, 18 retrospective, 1 prospective, and 5 case series studies) with 2446 patients (499 forward-viewing and 1947 side-viewing endoscopes) were analyzed. The pooled afferent loop intubation rate was higher with the forward-viewing endoscope (90.3%, 95% confidence interval (CI) 85.6-93.6 vs. 86.8%, 95% CI 82.8-89.9%). The pooled selective cannulation rate was higher with the side-viewing endoscope (92.3%, 95% CI 88.0-95.2 vs. 91.1%, 95% CI 87.2-93.9%). The pooled bowel perforation rate was higher with the side-viewing endoscope (3.6%, 95% CI 2.3-5.7 vs. 3.0%, 95% CI 1.7-5.3%). The pooled pancreatitis rate was higher with the forward-viewing endoscope (5.4%, 95% CI 3.6-8.0 vs. 2.5%, 95% CI 2.3-5.7%). The pooled bleeding rate was higher with the forward-viewing endoscope (3.0%, 95% CI 1.6-5.5 vs. 2.0%, 95% CI 1.4-3.0%). The heterogeneity among the studies was not significant. The publication bias was minimal.

CONCLUSION

This meta-analysis indicates that the forward-viewing endoscope is as safe and effective as conventional side-viewing endoscope for ERCP in patients with Billroth II gastrectomy.

A Novel Protocol Obviates Endoscope Sampling for Carbapenem-Resistant Enterobacteriaceae: Experience of a Center with a Prior Outbreak

BACKGROUND

Numerous published outbreaks, including one from our institution, have described endoscope-associated transmission of multidrug-resistant organisms (MDROs). Individual centers have adopted their own protocols to address this issue, including endoscope culture and sequestration. Endoscope culturing has drawbacks and may allow residual bacteria, including MDROs, to go undetected after high-level disinfection.

AIM

To report the outcome of our novel protocol, which does not utilize endoscope culturing, to address our outbreak.

METHODS

All patients undergoing procedures with elevator-containing endoscopes were asked to permit performance of a rectal swab. All endoscopes underwent high-level disinfection according to updated manufacturer's guidance. Additionally, ethylene oxide (EtO) sterilization was done in the high-risk settings of (1) positive response to a pre-procedure risk stratification questionnaire, (2) positive or indeterminate CRE polymerase chain reaction (PCR) from rectal swab, (3) refusal to consent for PCR or questionnaire, (4) purulent cholangitis or infected pancreatic fluid collections. Two endoscopes per weekend were sterilized on a rotational basis.

RESULTS

From September 1, 2015 to April 30, 2016, 556 endoscopy sessions were performed using elevator-containing endoscopes. Prompted EtO sterilization was done on 46 (8.3%) instances, 3 from positive/indeterminate PCR tests out of 530 samples (0.6%). No CRE transmission was observed during the study period. Damage or altered performance of endoscopes related to EtO was not observed.

CONCLUSION

In this pilot study, prompted EtO sterilization in high-risk patients has thus far eliminated endoscope-associated MDRO transmission, although no CRE infections were noted throughout the institution during the study period. Further studies and a larger patient sample will be required to validate these findings.

Current Issues in Duodenoscope-Associated Infections: Now Is the Time to Take Action

A duodenoscope has a very complex structure that contains many small parts which make reprocessing more challenging. The difficulty in cleaning duodenoscopes contributes to a higher risk of infection than that of conventional gastrointestinal endoscopes. However, a duodenoscope shares similar disinfection process with other gastrointestinal endoscopes. Recent outbreaks of carbapenem-resistant Enterobacteriaceae (CRE) infections associated with duodenoscopes used for endoscopic retrograde cholangiopancreatography procedures have raised many concerns worldwide. Duodenoscope-associated infections involving CRE or other multidrug-resistant bacteria pose a great threat to patients undergoing procedures using duodenoscopes and should be dealt with a great concern. Updated guidelines regarding cleaning and disinfection of duodenoscope needs to be developed urgently to prevent transmission of infection and ensure patient safety. Meanwhile, healthcare staff should pay special attention to thorough cleaning and disinfection of duodenoscopes.