Withdrawal of a novel-design duodenoscope ends outbreak of a VIM-2-producing Pseudomonas aeruginosa

Bacterial contamination and organic residue after reprocessing in duodenoscopes with disposable distal caps compared with duodenoscopes with fixed distal caps: a randomized trial

BACKGROUND AND AIMS

Newly designed duodenoscopes with disposable distal caps have been developed for better cleaning and preprocessing to reduce the risk of bacterial contamination (BC). We compared BC and organic residue of duodenoscopes with disposable distal caps and duodenoscopes with fixed distal caps after manual cleaning and high-level disinfection (HLD).

METHODS

Four hundred duodenoscopes were randomized into group A (fixed distal caps, n = 200) and group B (disposable distal caps, n = 200). After manual cleaning, samples from the elevator were submitted for culture. An adenosine triphosphate (ATP) test was performed for organic residue evaluation. Based on our previous data, ATP < 40 relative light units (RLUs) had 100% sensitivity with 100% negative predictive value to confirm no BC after reprocessing.

RESULTS

After manual cleaning, group A had a higher BC rate (14% vs 7%, P = .02), a higher proportion of duodenoscopes with ATP ≥ 40 RLUs (73.5% vs 57%, P = .001), and a higher mean of ATP level (226.6 vs 82.0 RLUs, P < .001) compared with group B. After HLD, the proportion of potential BC (ATP ≥ 40 RLUs) in group A was 2.7 times higher than group B (4% vs 1.5%, P = .13). Mean ATP level after HLD in the 2 groups was significantly lower than before the HLD procedure (group A, 24.2 vs 226.6 RLUs [P < .001]; group B, 20.4 vs 82.0 RLUs [P < .001], respectively).

CONCLUSIONS

After manual cleaning, duodenoscopes with disposable distal caps had significantly lower BC and organic residue than duodenoscopes with fixed distal caps. Only a few duodenoscopes from each group did not pass the ATP threshold after HLD.

Disposable duodenoscopes. Is healthcare system affordability the main hindrance?

The performance of an endoscopic procedure involves introducing an endoscope through the mouth or the anus, which may potentially lead to lethal infection. The risk increases when complex and difficult-to-clean scopes are used, as in the case of duodenoscopes. Side-viewing duodenoscopes are complex in design, with the camera and working channel exit located on one side of the endoscope's distal end, and with an elevator nail also located at this point for catheter redirection. This complex design may facilitate the presence of blind areas not easy to access for cleaning, resulting in suboptimal disinfection of the duodenoscope and therefore a higher risk of bacterial infection. This is of particular importance in particularly vulnerable patients like those who are immunosuppressed (e.g., transplanted patients) or have a malignant disease and are receiving chemotherapy. Moreover, in the era of ¨superbugs¨, like carbapenem-resistant Enterobacteriaceae, infection outbreaks related to endoscopic retrograde cholangiopancreatography (ERCP) have been reported with a significant mortality rate.

Current State and Future of Infection Prevention in Endoscopy

Gastrointestinal (GI) endoscopy units tend to be busy environments in which numerous categories of staff provide moderately complex procedural care to high volumes of patients. The prevention of infections of both patients and staff is a never-ending endeavor for both inpatient and outpatient environments. Necessary considerations must address patient-to-staff, staff-to-patient, environmental, and device-related transmission of infection. In addition to the typical environmental and interpersonal infection risks present in all medical environments, the major concern within the endoscopy suite relates to contamination and potential transmission via reusable devices and endoscopes. Our understanding of this ever-present issue has evolved over time and has become a major focus of scrutiny in the past 5 years. This significant problem has stimulated guidance and ingenuity by regulators, investigators, and industry. Most recently, the COVID-19 pandemic of 2020 to 21 has also added significant burdens to our infection control efforts in gastrointestinal endoscopy.

Education, training, and knowledge of infection control among endoscopy technicians and nurses

Our survey of 88 endoscopy technicians and nurses to determine their experience, training, and knowledge of infection control found that few personnel (<15%) received formal training in endoscope reprocessing or infection prevention before or after joining an endoscopy unit. While self-reported confidence in endoscope reprocessing was high (9 out of 10), knowledge of best practices in this regard lagged (average assessment score of 62%).

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.

A newly designed duodenoscope with detachable distal cap significantly reduces organic residue contamination after reprocessing

BACKGROUND

A newly designed duodenoscope with detachable distal cap may reduce bacterial contamination by allowing better access to the elevator. We compared bacterial contamination and organic residue evaluated by rapid adenosine triphosphate (ATP) test and culture from duodenoscopes with detachable vs. fixed distal caps after high-level disinfection (HLD).

METHODS

During December 2018-April 2019, 108 used newly designed duodenoscopes were enrolled. In group A (n = 54), the distal cap of the duodenoscope was detached before manual cleaning. In group B (n = 54), the distal cap was not detached. After HLD, samples were collected from the elevator, submitted for culture, and evaluated using the ATP test, using the cutoff value of 40 relative light units (RLUs).

RESULTS

After HLD, the proportion of potential bacterial contamination and organic residue in group A was significantly lower than in group B (37.0 % vs. 75.9 %; P  < 0.001; relative risk 0.49, 95 % confidence interval 0.33-0.71), and also confirmed by median ATP values (45.2 vs. 141.0 RLU; P  < 0.001). In group B, one sample culture was positive for nonpathogenic bacteria. Pathogenic bacteria were not found in any culture from either group.

CONCLUSIONS

The detachable distal cap was more effective at eliminating bacterial contamination and reducing organic residue than a fixed cap. Nonpathogenic bacteria were detected in the fixed cap group after reprocessing. The ATP test with 40 RLU cutoff is a practical method to ensure the cleanliness of duodenoscope reprocessing without the need to wait for bacterial culture results.

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.

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.

A Prospective, Randomized Comparison of Duodenoscope Reprocessing Surveillance Methods

Duodenoscope use in healthcare facilities has been associated with transmission of multidrug resistant pathogens between patients. To assist healthcare facilities in monitoring the quality of their duodenoscope reprocessing procedures and limit patient risk of infection, the Centers for Disease Control and Prevention (CDC) deployed voluntary interim duodenoscope sampling and culturing surveillance protocols in 2015. Though the interim methods were widely adopted, alternative surveillance protocols were developed and implemented at individual institutions. Here, we compared two sampling methods-the 2015 CDC interim protocol and an alternative protocol developed by the University of Wisconsin Hospitals and Clinics (UWHC). We hypothesized that the UWHC protocol would detect a higher incidence of bacterial contamination from reprocessed duodenoscopes. A total of 248 sampling events were performed at UWHC. The CDC protocol (n = 129 sampling events) required culturing samples collected from each duodenoscope after brushing its terminal end and flushing its lumen with sterile water. The UWHC protocol (n = 119 sampling events) required culturing samples collected from each duodenoscope after swabbing its elevator, immersing its terminal end into broth and flushing its lumen with saline. With the CDC method, 8.53% (n = 11) of the duodenoscopes sampled were positive for bacterial growth with 15 isolates recovered. Using the UWHC method, 15.13% (n = 18) of cultures were positive for bacterial growth with 20 isolates recovered. The relative risk of identifying a contaminated duodenoscope using the CDC interim method, however, was not different than when using the UWHC protocol. Mean processing time (27.35 and 5.11 minutes, p < 0.001) and total cost per sample event ($17.87 and $15.04) were lower using the UWHC method. As the UWHC protocol provides similar detection rates as the CDC protocol, the UWHC method is useful, provided the shorter processing time and lower cost to perform.

Duodenoscope-Associated Infections beyond the Elevator Channel: Alternative Causes for Difficult Reprocessing

OBJECTIVES

Duodenoscopes have been widely used for both diagnostic and therapeutic endoscopic retrograde cholangiopancreatography (ERCP) procedures, but recently, numerous outbreaks of multidrug-resistant organisms (MDRO) infections have been reported which has led to extensive research for their possible causes. Consequently, the aim of this study is to search for possible duodenoscope surface damages that could provide an alternative and plausible source of infections.

MATERIALS AND METHODS

In order to assess both outer and inner surfaces, a duodenoscope was dismantled and samples were taken from the outer resin polymer and from the air/water, elevator, and working (biopsy) channels that were characterized by FTIR, DSC, TGA, AFM, SEM techniques and the antimicrobial activity were tested.

RESULTS

Alterations were noticed on both the coating and working channel polymers, with external alterations increasing progressively from the proximal sample to the distal sample near the tip of the scope. However, the results showed that the coating surface was still efficient against bacterial adhesion. Changes in surface texture and also morphological changes were shown.

CONCLUSIONS

The study describes the impact of routine procedural use and reprocessing cycles on the duodenoscope, showing that these may possibly make it susceptible to bacterial contamination and MDRO biofilm formation due to difficult reprocessing of the altered surfaces.

Transmission of Mobile Colistin Resistance (mcr-1) by Duodenoscope

BACKGROUND

Clinicians increasingly utilize polymyxins for treatment of serious infections caused by multidrug-resistant gram-negative bacteria. Emergence of plasmid-mediated, mobile colistin resistance genes creates potential for rapid spread of polymyxin resistance. We investigated the possible transmission of Klebsiella pneumoniae carrying mcr-1 via duodenoscope and report the first documented healthcare transmission of mcr-1-harboring bacteria in the United States.

METHODS

A field investigation, including screening targeted high-risk groups, evaluation of the duodenoscope, and genome sequencing of isolated organisms, was conducted. The study site included a tertiary care academic health center in Boston, Massachusetts, and extended to community locations in New England.

RESULTS

Two patients had highly related mcr-1-positive K. pneumoniae isolated from clinical cultures; a duodenoscope was the only identified epidemiological link. Screening tests for mcr-1 in 20 healthcare contacts and 2 household contacts were negative. Klebsiella pneumoniae and Escherichia coli were recovered from the duodenoscope; neither carried mcr-1. Evaluation of the duodenoscope identified intrusion of biomaterial under the sealed distal cap; devices were recalled to repair this defect.

CONCLUSIONS

We identified transmission of mcr-1 in a United States acute care hospital that likely occurred via duodenoscope despite no identifiable breaches in reprocessing or infection control practices. Duodenoscope design flaws leading to transmission of multidrug-resistant organsisms persist despite recent initiatives to improve device safety. Reliable detection of colistin resistance is currently challenging for clinical laboratories, particularly given the absence of a US Food and Drug Administration-cleared test; improved clinical laboratory capacity for colistin susceptibility testing is needed to prevent the spread of mcr-carrying bacteria in healthcare settings.

Efficacy of low-temperature plasma-activated gas disinfection against biofilm on contaminated GI endoscope channels

BACKGROUND AND AIMS

It has been increasingly recognized that the safety of GI endoscopes needs to be improved by addressing the small margin of safety of high-level disinfectants (HLDs) and the failure of HLDs to clear multidrug-resistant organisms and biofilms. There is also an unmet need for effective low-temperature sterilization techniques that have a clear pathway for U.S. Food and Drug Administration clearance. Here, we report the results of our investigation of a novel argon plasma-activated gas (PAG) for disinfection and potentially sterilization of biofilm-contaminated endoscopic channels.

METHODS

Test polytetrafluoroethylene channel segments were contaminated with 4-, 24- and 48-hour luminal biofilms of methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, or Escherichia coli and were treated by PAG flowing for up to 9 minutes. After PAG treatment, inactivation and dispersal of luminal bacterial biofilms and their regrowth in 48 hours were evaluated. Reactive species induced by PAG were measured with colorimetric probes and electron spin resonance spectrometry. Surface morphology and elemental composition of PAG-treated channel material were analyzed with scanning electron microscopy.

RESULTS

PAG treatment for 9 minutes led to more than 8 log reduction of viable cells and dispersal of 24- and 48-hour luminal biofilms of all 3 bacteria and to suppression of their regrowth, whereas it resulted in little morphologic abnormalities in channel material. Ozone concentration of PAG fell to below .01 ppm within 30 seconds of switching off the plasma. PAG-treated deionized water was acidified with numerous types of reactive species, each with a concentration some 3 orders of magnitude or more below its bacterial inhibition concentration.

CONCLUSIONS

PAG is capable of effectively and rapidly disinfecting luminal bacterial biofilms and offers an alternative to the step of HLDs and/or ethylene oxide in the endoscope reprocessing procedure with safety to personnel and environment.

Scoping the scope: endoscopic evaluation of endoscope working channels with a new high-resolution inspection endoscope (with video)

BACKGROUND AND AIMS

Outbreaks of transmission of infection related to endoscopy despite reported adherence to reprocessing guidelines warrant scrutiny of all potential contributing factors. Recent reports from ambulatory surgery centers indicated widespread significant occult damage within endoscope working channels, raising concerns regarding the potential detrimental impact of this damage on the adequacy of endoscope reprocessing.

METHODS

We inspected working channels of all 68 endoscopes at our academic institution using a novel flexible inspection endoscope. Inspections were recorded and videos reviewed by 3 investigators to evaluate and rate channel damage and/or debris. Working channel rinsates were obtained from all endoscopes, and adenosine triphosphate (ATP) bioluminescence was measured.

RESULTS

Overall endoscope working channel damage was rated as minimal and/or mild and was consistent with expected wear and tear (median 1.59 on our 5-point scale). Our predominant findings included superficial scratches (98.5%) and scratches with adherent peel (76.5%). No channel perforations, stains, or burns were detected. The extent of damage was not predicted by endoscope age. Minor punctate debris was common, and a few small drops of fluid were noted in 42.6% of endoscopes after reprocessing and drying. The presence of residual fluid predicted higher ATP bioluminescence values. The presence of visualized working channel damage or debris was not associated with elevated ATP bioluminescence values.

CONCLUSION

The flexible inspection endoscope enables high-resolution imaging of endoscope working channels and offers endoscopy units an additional modality for endoscope surveillance, potentially complementing bacterial cultures and ATP values. Our study, conducted in a busy academic endoscopy unit, indicated predominately mild damage to endoscope working channels, which did not correlate with elevated ATP values.

Adenosine triphosphate bioluminescence for bacteriologic surveillance and reprocessing strategies for minimizing risk of infection transmission by duodenoscopes

BACKGROUND AND AIMS

Recent outbreaks of duodenoscope-transmitted infections underscore the importance of adequate endoscope reprocessing. Adenosine triphosphate (ATP) bioluminescence testing allows rapid evaluation of endoscopes for bacteriologic/biologic residue. In this prospective study we evaluate the utility of ATP in bacteriologic surveillance and the effects of endoscopy staff education and dual cycles of cleaning and high-level disinfection (HLD) on endoscope reprocessing.

METHODS

ATP bioluminescence was measured after precleaning, manual cleaning, and HLD on rinsates from suction-biopsy channels of all endoscopes and elevator channels of duodenoscopes/linear echoendoscopes after use. ATP bioluminescence was remeasured in duodenoscopes (1) after re-education and competency testing of endoscopy staff and subsequently (2) after 2 cycles of precleaning and manual cleaning and single cycle of HLD or (3) after 2 cycles of precleaning, manual cleaning, and HLD.

RESULTS

The ideal ATP bioluminescence benchmark of <200 relative light units (RLUs) after manual cleaning was achieved from suction-biopsy channel rinsates of all endoscopes, but 9 of 10 duodenoscope elevator channel rinsates failed to meet this benchmark. Re-education reduced RLUs in duodenoscope elevator channel rinsates after precleaning (23,218.0 vs 1340.5 RLUs, P < .01) and HLD (177.0 vs 12.0 RLUs, P < .01). After 2 cycles of manual cleaning/HLD, duodenoscope elevator channel RLUs achieved levels similar to sterile water, with corresponding negative cultures.

CONCLUSIONS

ATP testing offers a rapid, inexpensive alternative for detection of endoscope microbial residue. Re-education of endoscopy staff and 2 cycles of cleaning and HLD decreased elevator channel RLUs to levels similar to sterile water and may therefore minimize the risk of transmission of infections by duodenoscopes.

Duodenoscope hang time does not correlate with risk of bacterial contamination

BACKGROUND

Current professional guidelines recommend a maximum hang time for reprocessed duodenoscopes of 5-14 days. We sought to study the association between hang time and risk of duodenoscope contamination.

METHODS

We analyzed cultures of the elevator mechanism and working channel collected in a highly standardized fashion just before duodenoscope use. Hang time was calculated as the time from reprocessing to duodenoscope sampling. The relationship between hang time and duodenoscope contamination was estimated using a calculated correlation coefficient between hang time in days and degree of contamination on the elevator mechanism and working channel.

RESULTS

The 18 study duodenoscopes were cultured 531 times, including 465 (87.6%) in the analysis dataset. Hang time ranged from 0.07-39.93 days, including 34 (7.3%) with hang time ≥7.00 days. Twelve cultures (2.6%) demonstrated elevator mechanism and/or working channel contamination. The correlation coefficients for hang time and degree of duodenoscope contamination were very small and not statistically significant (-0.0090 [P = .85] for elevator mechanism and -0.0002 [P = 1.00] for working channel). Odds ratios for hang time (dichotomized at ≥7.00 days) and elevator mechanism and/or working channel contamination were not significant.

CONCLUSIONS

We did not find a significant association between hang time and risk of duodenoscope contamination. Future guidelines should consider a recommendation of no limit for hang time.

Current Practice of Duodenoscope Reprocessing

Numerous outbreaks of duodenoscope-associated transmission of multi-drug resistant bacteria have recently been reported. Unlike prior episodes of endoscope-transmitted infections, the latest outbreaks have occurred despite strict adherence to duodenoscope reprocessing guidelines. The current standard for all flexible endoscope reprocessing includes pre-cleaning, leak testing, an additional manual cleaning step, and high-level disinfection. When these steps are strictly followed, the risk of infection transmission during endoscopy is exceedingly rare. However, due to its complex design, the duodenoscope may not be able to be adequately disinfected using the current reprocessing standards. Supplemental measures to enhance scope reprocessing have subsequently been recommended to reduce the infection risk in patients undergoing endoscopic retrograde cholangiopancreatography. These methods are likely short-term solutions that have yet to be validated regarded their effectiveness. Additional approaches to monitor the quality of duodenoscope reprocessing may also be useful. Ultimately, a definitive, yet logistically feasible, method of duodenoscope reprocessing is required to ensure the safety of our patients.

Risk factors associated with the transmission of carbapenem-resistant Enterobacteriaceae via contaminated duodenoscopes

BACKGROUND AND AIMS

The duodenoscopes used to perform ERCP have been implicated in several outbreaks of carbapenem-resistant Enterobacteriaceae (CRE) infection. The risk factors for CRE transmission via contaminated duodenoscopes remain unclear.

METHODS

In this retrospective, single-center, case-control study, all patients who underwent ERCP with either 1 of 2 contaminated duodenoscopes were evaluated. We compared the patients who acquired CRE (active infection or colonization) with those who did not.

RESULTS

Between October 3, 2014, and January 28, 2015, a total of 125 procedures were performed on 115 patients by using either of the contaminated duodenoscopes. Culture data were available for 104 of the 115 exposed patients (90.4%). Among these patients, 15 (14.4%) became actively infected (n = 8, 7.7%) or colonized (n = 7, 6.7%) with CRE. On univariate analysis, recent antibiotic exposure (66.7% vs 37.1%; P = .046), active inpatient status (60.0% vs 28.1%; P = .034), and a history of cholangiocarcinoma (26.7% vs 3.4%; P = .008) were patient characteristics associated with an increased risk of CRE infection. Biliary stent placement (53.3% vs 22.5%; P = .024) during ERCP was a significant procedure-related risk factor. After adjusting for cholangiocarcinoma, biliary stent placement (odds ratio 3.62; 95% confidence interval, 1.12-11.67), and active inpatient status (odds ratio 3.74; 95% confidence interval, 1.15-12.12) remained independent risk factors for CRE transmission.

CONCLUSIONS

In patients undergoing ERCP with a contaminated duodenoscope, biliary stent placement, a diagnosis of cholangiocarcinoma, and active inpatient status are associated with an increased risk of CRE transmission.