A prospective study of the efficacy of routine decontamination for gastrointestinal endoscopes and the risk factors for failure

Evaluation of a novel disposable endoscope for retroflexed endoscopic rubber band ligation of internal hemorrhoids: a randomized pilot study

PURPOSE

Retroflexed endoscopic rubber band ligation (ERBL) for treating Grade II and III internal hemorrhoids using disposable endoscopes has not been previously assessed. We therefore compared the safety and effectiveness of ERBL for internal hemorrhoids using novel disposable endoscopes versus traditional reusable endoscopes.

METHODS

This prospective randomized controlled trial involved 42 patients who underwent ERBL for Grade II and III internal hemorrhoids using either a disposable endoscope (n = 21) or a reusable endoscope (n = 21). Safety was assessed by the incidence of equipment failure, device-related adverse events, and in-procedure stability of vital signs. Effectiveness was assessed by the postoperative therapeutic effect, feasibility of retroflexed ERBL, and incidence of complications.

RESULTS

In terms of safety, no life-threatening events, equipment failure, or device-related adverse effects occurred during the procedures in either group. The rate of diastolic blood pressure stability was significantly different between the two groups (P = .049), but the rates of systolic blood pressure and heart rate stability were similar. In terms of effectiveness, the therapeutic effects on postoperative Day 30 were similar in both groups. Image clarity and endoscopic flexibility in the disposable endoscope group were mildly inferior to those in the reusable endoscope group, but without statistical significance. Matching between the endoscope and ligating device was 100% in both groups. The incidence of complications on postoperative Days 1 and 10 was not significantly different between the two groups.

CONCLUSION

Compared with reusable endoscopes, disposable endoscopes are equally safe, feasible, and reliable in ERBL for internal hemorrhoids.

How biofilm changes our understanding of cleaning and disinfection

Biofilms are ubiquitous in healthcare settings. By nature, biofilms are less susceptible to antimicrobials and are associated with healthcare-associated infections (HAI). Resistance of biofilm to antimicrobials is multifactorial with the presence of a matrix composed of extracellular polymeric substances and eDNA, being a major contributing factor. The usual multispecies composition of environmental biofilms can also impact on antimicrobial efficacy. In healthcare settings, two main types of biofilms are present: hydrated biofilms, for example, in drains and parts of some medical devices and equipment, and environmental dry biofilms (DSB) on surfaces and possibly in medical devices. Biofilms act as a reservoir for pathogens including multi-drug resistant organisms and their elimination requires different approaches. The control of hydrated (drain) biofilms should be informed by a reduction or elimination of microbial bioburden together with measuring biofilm regrowth time. The control of DSB should be measured by a combination of a reduction or elimination in microbial bioburden on surfaces together with a decrease in bacterial transfer post-intervention. Failure to control biofilms increases the risk for HAI, but biofilms are not solely responsible for disinfection failure or shortcoming. The limited number of standardised biofilm efficacy tests is a hindrance for end users and manufacturers, whilst in Europe there are no approved standard protocols. Education of stakeholders about biofilms and ad hoc efficacy tests, often academic in nature, is thus paramount, to achieve a better control of biofilms in healthcare settings.

Significant increased bacterial contamination with endoscope overnight and weekend storage times

BACKGROUND AND AIM

Forced-air drying (FAD) cabinets are recommended for storage of reprocessed endoscopes, but financial constraints prevent their universal application. The study aimed to determine bacterial contamination in flexible gastroscopes (FG) channels after storage, in a cabinet with filtered air and UV lights, but without FAD.

METHODS

Eight FG in clinical use in an endoscopy service of a large Brazilian hospital were sampled: immediately "Time zero" (N = 50), 12 h "Time 1" (N = 25), and 60 h "Time 2" (N = 25) after reprocessing. Following a flush-brush-flush of channels, 40-mL sterile water and 3 cm of the brush were collected. Each sample was divided, filtered onto two 0.22-μm membranes, and incubated in media without or with disinfectant neutralizer. Automated method was used for identification and antibiotic resistance test of isolated bacteria.

RESULTS

Bacterial contamination in times "1" and "2" was 5.9 and 16.1 times greater than that of "Time zero," respectively. Number of positive cultures in media with and without neutralizer was similar at times "1" and "2," while media with neutralizer produced more positive cultures at "Time zero." Most bacteria isolated at "Time 2" were Gram-negative rods (52.3%) and showed resistance to one or more antibiotics (65%).

CONCLUSION

Bacterial contamination was detected on reprocessed FG stored in non-FAD cabinets overnight (12 h) and increased with longer storage time (60 h). The contamination source is likely to be bacteria in biofilm which multiply in the absence of FAD. Evidence-based criteria should be available for storage time according to the cabinet available.

Adoption of Improved Reprocessing Decreased Microbiological Non-Compliance for Bronchoscopes

BACKGROUND

In the past few decades, the inadequate reprocessing of bronchoscopes has been associated with several serious outbreaks caused by multidrug-resistant microorganisms. In this study we evaluated the improvement in the quality of reprocessing in a Bronchoscopy Unit (BU), after the introduction of a new procedure.

METHODS

In 2019, observational and clinical audits were conducted in the BU. After the introduction of an improved procedure in 2020, a microbiological surveillance plan was implemented in 2021.

RESULTS

In 2019, 13 of 22 bronchoscopes (59%) resulted as non-compliant, 18% as high concern organisms (HCO) and 36.4% as high microbial count (≥100 CFU/all channels) and HCO. The most frequent microorganisms were Staphylococcus aureus (38.5%) and NDM-producing Klebsiella pneumoniae (15.4%). The bronchoscopes were stored inside their transport cases, which in some cases were found to be contaminated by the same strains isolated on the bronchoscopes (Enterobacter gergoviae and Vibrio alginolyticus). In 2021, all 31 bronchoscopes were sampled at least three times and 13/99 (13.1%) resulted as non-compliant, mostly K. pneumoniae (4.04%). Contamination level increases weakly in bronchoscopes in use for more than 14 years (R = 0.32).

CONCLUSIONS

The adoption of an improved reprocessing procedure decreased the non-compliance of bronchoscopes, increasing the quality of the process and patient safety.

Dual species dry surface biofilms; Bacillus species impact on Staphylococcus aureus survival and surface disinfection

AIMS

Dry surface biofilms (DSB) survive on environmental surfaces throughout hospitals, able to resist cleaning and disinfection interventions. This study aimed to produce a dual species DSB and explore the ability of commercially available wipe products to eliminate pathogens within a dual species DSB and prevent their transfer.

METHODS AND RESULTS

Staphylococcus aureus was grown with two different species of Bacillus on stainless steel discs, over 12 days using sequential hydration and dehydration phases. A modified version of ASTM 2967-15 was used to test six wipe products including one water control with the Fitaflex Wiperator. Staphylococcus aureus growth was inhibited when combined with Bacillus subtilis. Recovery of S. aureus on agar from a dual DSB was not always consistent. Our results did not provide evidence that Bacillus licheniformis protected S. aureus from wipe action. There was no significant difference of S. aureus elimination by antimicrobial wipes between single and dual species DSB. B. licheniformis was easily transferred by the wipe itself and to new surfaces both in a single and dual species DSB, whilst several wipe products inhibited the transfer of S. aureus from wipe. However, S. aureus direct transfer to new surfaces was not inhibited post-wiping.

CONCLUSIONS

Although we observed that the dual DSB did not confer protection of S. aureus, we demonstrated that environmental species can persist on surfaces after disinfection treatment. Industries should test DSB against future products and hospitals should consider carefully the products they choose.

SIGNIFICANCE AND IMPACT OF THE STUDY

To our knowledge, this is the first study reporting on the production of a dual species DSB. Multispecies DSB have been identified throughout the world on hospital surfaces, but many studies focus on single species biofilms. This study has shown that DSB behave differently to hydrated biofilms.

A cost comparison between reusable flexible and disposable laryngoscopes

OBJECTIVES

To compare the costs of disposable laryngoscopes to reusable scopes in outpatient and inpatient settings.

METHODS

The total variable and fixed costs involved in flexible scope reprocessing were collected from two general otolaryngology clinics, a pediatric otolaryngology clinic, and a children's hospital. Variable costs of disposable materials and labor were collected from 65 scope reprocessing events to identify the cost of reprocessing. Fixed costs of scope maintenance, monitors, video towers, and storage equipment were collected from financial records. Fixed and variable costs were analyzed to identify the cost per scope event. The costs were then compared to a theoretical model where disposable scopes were used to meet the volume demands of each clinic and children's hospital setting. The model of disposable scopes was generated after obtaining volume costs specific to each setting from a disposable scope company.

RESULTS

The average cost of a reusable scope model per scope event was $66.02 ± 4.49 at the three clinics and $130.66 at the children's hospital. The average cost of the disposable scope model per scope event was $152.55 ± 0.55 in the three clinics and $172.61 in the children's hospital. The cost differences were $86.53 ± 3.96 and $41.95 respectively.

CONCLUSIONS

In an outpatient clinic, reusable scopes are less expensive than a disposable scope model. In children's hospital inpatient setting, the difference in costs between disposable and reusable scopes is lower. When considering other non-economic factors, disposable scopes may be a feasible option, especially in the children's hospital setting.

The feasibility and safety of disposable endoscope vs. conventional endoscope for upper gastrointestinal tract examination: a multicenter, randomized, parallel, non-inferiority trial

Background A disposable upper gastrointestinal endoscope can effectively decrease infectious outbreaks associated with endoscope reuse. In the present study, we aimed to evaluate the feasibility and safety of a disposable endoscope for upper gastrointestinal examination.

Methods In a prospective, randomized trial, 144 upper endoscopic procedures were allocated to either the disposable endoscope group or the conventional endoscope group. The primary outcomes were rates of excellent and good image qualities and maneuverability satisfaction. The second outcome included procedure duration, endoscopic diagnosis, and adverse events.

Results A total of 144 subjects were enrolled in the present analysis and prospectively randomized to 2 study groups. Finally, 70 and 69 subjects were enrolled in the novel disposable endoscope group and the conventional endoscope group, respectively, due to the schedule cancellation of 5 subjects. The baseline characteristics of the patients were similar in both groups. The excellent and good image quality rates and maneuverability satisfaction of the novel disposable endoscope were not inferior to the conventional endoscope (p = 0.99 and p = 0.99, respectively). Moreover, no significant between-group difference was observed in the endoscopic results and adverse events (p = 0.30 and p = 1, respectively). However, the procedure duration in the novel disposable endoscope was longer compared with the conventional endoscope (8.40 ± 4.28 min vs. 5.12 ± 2.65 min, p < 0.001).

Conclusions The novel disposable endoscope was as safe, effective, and maneuverable as a conventional endoscope. However, the novel disposable endoscope was associated with a longer procedure duration.

Smart pills for gastrointestinal diagnostics and therapy

Ingestible smart pills have the potential to be a powerful clinical tool in the diagnosis and treatment of gastrointestinal disease. Though examples of this technology, such as capsule endoscopy, have been successfully translated from the lab into clinically used products, there are still numerous challenges that need to be overcome. This review gives an overview of the research being done in the area of ingestible smart pills and reports on the technical challenges in this field.

Microbiological Surveillance of Endoscopes in a Southern Italian Transplantation Hospital: A Retrospective Study from 2016 to 2019

Endoscopes are medical instruments that are used routinely in health structures. Due to their invasive nature and contact with many patients, they may cause hospital-acquired infections if not disinfected correctly. To ensure a high-level disinfection procedure or reprocessing, since the methods currently adopted in our institute are adequate, we evaluated retrospectively the presence of microorganisms in our endoscopes after reprocessing. Microbiological surveillance was performed from January 2016 to December 2019 in the instruments in use in our endoscopic room after reprocessing. In total, 35 endoscopes (3 duodenoscopes, 3 echoendoscopes, 12 bronchoscopes, 5 colonoscopes, and 12 gastroscopes) were evaluated for the presence of microorganisms, including multidrug-resistant pathogens and indicator microorganisms (IMOs). Our procedures were in agreement with an internal protocol based on Italian, international, and the Center for Disease Control and Prevention (CDC) recommendations. Of a total of 811 samples, 799 (98.5%) complied with the regulatory guidelines, while 9 (1.1%) were positive for IMOs, and 3 (0.4%) displayed more than 10 colony-forming units (CFU) of environmental and commensal pathogens. Our results show that the internal reprocessing protocol is very efficient, leading to a very low number of observed contaminations, and it could be easily implemented by other health facilities that face a huge number of hospital-acquired infections due to incorrectly disinfected endoscopes.

Improving the Reprocessing Quality of Flexible Thermolabile Endoscopes: How to Learn from Mistakes

Background: Failure in the reprocessing of thermolabile flexible endoscopes has been reported as one of the most important threats to patient health. Method: A case report and observational study was conducted, from August 2014 to December 2019, in the Digestive Endoscopy Unit of a University Hospital in Italy, where two cases of Klebsiella pneumoniae carbapenemase (KPC)-producing Klebsiella pneumoniae infections in patients undergoing endoscopic retrograde cholangio-pancreatography were observed. Following the risk/safety management practices, an epidemiological investigation was started, duodenoscopes were removed from use and the reprocessing practices reviewed. Moreover, microbiological surveillance of endoscopes was carried out according to the CDC guidelines. Results: In the first phase of sampling, 10/10 (100%) endoscopes were found to be non-compliant, of which 7 showed results for high-concern organisms (HCOs), such as KPC-K. pneumoniae, P. aeruginosa and E. coli. After implementing corrective actions, 12 out of 17 endoscopes were found to be non-compliant (70.5%), of which 8 showed results for HCOs, such as KPC-K. oxytoca and P. aeruginosa. During the last year of regular microbiological surveillance, only 23% of endoscopes (35/152) were found to be non-compliant, of which 7 showed results for HCOs, such as NDM-K. pneumoniae, P. aeruginosa and A. baumannii. The crucial issues were related to samples collected from the internal channels of duodenoscopes. Conclusion: Managing the risk associated with the reprocessing of digestive endoscopes, through risk assessment at every stage of the process, is important for the prevention of infections associated with the use of these device.

Remote video auditing in the endoscopy unit for evaluation of duodenoscope reprocessing in a tertiary care center

BACKGROUND : A significant proportion of duodenoscope-transmitted infections have resulted from errors related to reprocessing. Remote video auditing (RVA) is a tool that can monitor reprocessing compliance but it has not been previously evaluated in a tertiary care setting. The aims of this study were to evaluate: 1) RVA feasibility in a tertiary care setting (defined as the ability to audit every step of duodenoscope reprocessing without delaying the next procedure due to unavailability of duodenoscopes); and 2) the use of RVA as a compliance monitoring tool. METHODS : This was a prospective study at a tertiary care center. A video camera with offsite monitoring was installed in March 2018. Auditors delivered a compliance score after each procedure. The duodenoscope was not used until it passed the audit. Feasibility and compliance data were collected from April 2018 to August 2019 after a 1-month run-in phase. Both per-step compliance and overall 100 % compliance rates were measured. RESULTS : Of 743 duodenoscope reprocessing procedures, 32 666 individual steps were audited and 99.9 % of the steps were fully viewable. The mean time per audit was 38.3 minutes, the mean duodenoscope turnover time was 76.1 minutes, and there were no delays to the next procedure due to unavailability of duodenoscopes. The per-step compliance rate was 99.5 % but the overall 100 % compliance rate was 90.3 %. CONCLUSIONS : The use of RVA in duodenoscope reprocessing was feasible and promoted sustained high-level compliance in a tertiary care center.

Nationwide risk analysis of duodenoscope and linear echoendoscope contamination

BACKGROUND AND AIMS

Contaminated duodenoscopes and linear echoendoscopes (DLEs) pose a risk for infectious outbreaks. To identify DLEs and reprocessing risk factors, we combined the data from the previously published nationwide cross-sectional PROCESS 1 study (Prevalence of contamination of complex endoscopes in the Netherlands) with the follow-up PROCESS 2 study.

METHODS

We invited all 74 Dutch DLE centers to sample ≥2 duodenoscopes during PROCESS 1, and all duodenoscopes as well as linear echoendoscopes during PROCESS 2. The studies took place 1 year after another. Local staff sampled each DLE at ≤6 sites according to uniform methods explained by online videos. We used 2 contamination definitions: (1) any microorganism with ≥20 colony-forming units (CFU)/20 mL (AM20) and (2) presence of microorganisms with GI or oral origin, independent of CFU count (MGOs). We assessed the factors of age and usage by performing an analysis of pooled data of both PROCESS studies; additional factors including reprocessing characteristics were only recorded in PROCESS 2.

RESULTS

Ninety-seven percent of all Dutch centers (72 of 74; PROCESS 1, 66; PROCESS 2, 61) participated in one of the studies, sampling 309 duodenoscopes and 64 linear echoendoscopes. In total, 54 (17%) duodenoscopes and 8 (13%) linear echoendoscopes were contaminated according to the AM20 definition. MGOs were detected on 47 (15%) duodenoscopes and 9 (14%) linear echoendoscopes. Contamination was not age or usage dependent (all P values ≥.27) and was not shown to differ between the reprocessing characteristics (all P values ≥.01).

CONCLUSIONS

In these nationwide studies, we found that DLE contamination was independent of age and usage. These results suggest that old and heavily used DLEs, if maintained correctly, have a similar risk for contamination as new DLEs. The prevalence of MGO contamination of ∼15% was similarly high for duodenoscopes as for linear echoendoscopes, rendering patients undergoing ERCP and EUS at risk for transmission of microorganisms.

Contribution of usage to endoscope working channel damage and bacterial contamination

BACKGROUND

Biofilm formation has been shown to be associated with damaged areas of endoscope channels. It was hypothesized that the passage of instruments and brushes through endoscope channels during procedures and cleaning contributes to channel damage, bacterial attachment and biofilm formation.

AIM

To compare surface roughness and bacterial attachment in used and new endoscope channels in vivo and in vitro.

METHODS

Surface roughness of 10 clinically used (retired) and seven new colonoscope biopsy channels was analysed by a surface profiler. For the in-vitro study, a flexible endoscope biopsy forceps was passed repeatedly through a curved 3.0-mm-diameter Teflon tube 100, 200 and 500 times. Atomic force microscopy was used to determine the degree of inner surface damage. The number of Escherichia coli or Enterococcus faecium attached to the inner surface of the new Teflon tube and the tube with 500 forceps passes in 1 h at 37^oC was determined by culture.

RESULTS

The average surface roughness of the used biopsy channels was found to be 1.5 times greater than that of the new biopsy channels (P=0.03). Surface roughness of Teflon tubes with 100, 200 and 500 forceps passes was 1.05-, 1.12- and 3.2-fold (P=0.025) greater than the roughness of the new Teflon tubes, respectively. The number of E. coli and E. faecium attached to Teflon tubes with 500 forceps passes was 2.9-fold (P=0.021) and 4.3-fold (P=0.004) higher compared with the number of E. coli and E. faecium attached to the new Teflon tubes, respectively.

CONCLUSION

An association was found between endoscope usage with damage to the biopsy channel and increased bacterial attachment.

An update on gastrointestinal endoscopy-associated infections and their contributing factors

INTRODUCTION

During clinical use, gastrointestinal endoscopes are grossly contaminated with patient's native flora. These endoscopes undergo reprocessing to prevent infectious transmission upon future use. Endoscopy-associated infections and outbreaks have been reported, with a recent focus on the transmission of multi-drug resistant organisms. This review aims to provide an update on endoscopy-associated infections, and the factors contributing to their occurrence.

METHODS

PubMed, ScienceDirect, and CINAHL were searched for articles describing gastrointestinal endoscopy-associated infections and outbreaks published from 2008 to 2018. Factors contributing to their occurrence, and the outcomes of each outbreak were also examined.

RESULTS

This review found 18 articles, 16 of which described duodenoscope-associated infections, and the remaining two described colonoscope- and gastroscope-associated infection respectively. Outbreaks were reported from the United States, France, China, Germany, the Netherlands and the United Kingdom. The causative organisms reported were Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli and Salmonella enteritidis.

CONCLUSIONS

A number of factors, including lapses in reprocessing, biofilm formation, endoscope design issues and endoscope damage, contribute to gastrointestinal endoscopy associated infection. Methods of improving endoscope reprocessing, screening for contamination and evaluating endoscope damage may be vital to preventing future infections and outbreaks.

The validity of adenosine triphosphate measurement in detecting endoscope contamination

BACKGROUND

Endoscopic procedures are vital to gastrointestinal disease diagnosis and management, but risk infection transmission. In Australia, endoscopes undergo monthly-to-quarterly microbiological testing, to prevent patient infection. Endoscopes are used more frequently, meaning contamination may not be detected by this surveillance before infection transmission occurs.

AIM

To evaluate the use of adenosine triphosphate (ATP) measurement, alongside standard microbiological cultures, in detecting endoscope contamination before high-level disinfection. Using these results, we also aimed to confirm the efficacy of manual cleaning in reducing levels of ATP and cfu/mL.

METHODS

Seventeen in-clinical-use gastroscopes and 24 in-clinical-use colonoscopes from the Liverpool Hospital Endoscopy unit were sampled across three separate cleaning stages before high-level disinfection. Colony counts and ATP measurements were then performed on these samples.

FINDINGS

The correlation between the cfu/mL and RLU of samples collected from colonoscopes was 0.497 (95% confidence interval: 0.28-0.66; P < 0.0001). The correlation between cfu/mL and RLU for samples collected from gastroscopes was 0.377 (0.08-0.61; P = 0.0138). RLU and cfu/mL values were shown to fall significantly (P < 0.005) following precleaning and manual cleaning.

CONCLUSION

There was a significant correlation between ATP and cfu/mL measured from samples collected before high-level disinfection. Precleaning and manual cleaning were shown to reduce ATP and microbiological load significantly. ATP measurement can be performed within minutes with little training and produces results that are easy to interpret. These findings warrant further research on the utility of ATP measurement as a screening tool for detecting endoscope contamination after high-level disinfection.

Is an endoscopic examination associated with transfusion-transmissible infections? A systematic review and meta-analysis

BACKGROUND

The purpose of a donor medical questionnaire is to identify the blood donor's history relative to the current known blood-safety risks. A temporary deferral from blood donation after an endoscopic examination is enforced because of the reusable nature of the endoscope and close contact with the inner body. The objective of this systematic review was to find the best available evidence on the association between an endoscopic examination and the risk of transfusion-transmissible infections.

METHODS

Studies from five databases investigating the link between an endoscopic examination and transfusion-transmissible infections (hepatitis B virus, hepatitis C virus, human immunodeficiency virus infection, Treponema pallidum) were retained and assessed independently by two reviewers. The association between endoscopy and transfusion-transmissible infections was identified by conducting meta-analyses and calculating pooled effect measures (odds ratios and 95% confidence intervals). The Grading of Recommendations, Assessment, Development, and Evaluation methodology was used to assess the quality of evidence.

RESULTS

We identified 7571 references and finally included 29 observational studies. A significant association between an endoscopic examination and hepatitis B virus infection (pooled odds ratio [OR], 2.21; 95% confidence interval [CI], 1.26-3.86; p = 0.005) or hepatitis C virus infection (pooled OR 1.76, 95% CI, 1.45-2.14; p < 0.00001) was found. The level of evidence was considered as "very low" due to the type of study design (i.e., observational) and indirect study populations (i.e., no blood donor populations).

CONCLUSION

An endoscopic examination is associated with an increased hepatitis B virus or hepatitis C virus infection risk. Further high-quality trials are required to formulate stronger evidence-based recommendations on endoscopic examination as a blood donor deferral criterion.

Sterile Reverse Osmosis Water Combined with Friction Are Optimal for Channel and Lever Cavity Sample Collection of Flexible Duodenoscopes

Introduction

Simulated-use buildup biofilm (BBF) model was used to assess various extraction fluids and friction methods to determine the optimal sample collection method for polytetrafluorethylene channels. In addition, simulated-use testing was performed for the channel and lever cavity of duodenoscopes.

Materials and methods

BBF was formed in polytetrafluorethylene channels using Enterococcus faecalis, Escherichia coli, and Pseudomonas aeruginosa. Sterile reverse osmosis (RO) water, and phosphate-buffered saline with and without Tween80 as well as two neutralizing broths (Letheen and Dey-Engley) were each assessed with and without friction. Neutralizer was added immediately after sample collection and samples concentrated using centrifugation. Simulated-use testing was done using TJF-Q180V and JF-140F Olympus duodenoscopes.

Results

Despite variability in the bacterial CFU in the BBF model, none of the extraction fluids tested were significantly better than RO. Borescope examination showed far less residual material when friction was part of the extraction protocol. The RO for flush-brush-flush (FBF) extraction provided significantly better recovery of E. coli (p = 0.02) from duodenoscope lever cavities compared to the CDC flush method.

Discussion and conclusion

We recommend RO with friction for FBF extraction of the channel and lever cavity of duodenoscopes. Neutralizer and sample concentration optimize recovery of viable bacteria on culture.

Duodenoscopy related infection risk and duodenoscope cleaning and disinfection

With the development of minimally invasive techniques, duodenoscope, as an instrument for diagnosis and treatment of pancreaticobiliary diseases, has been gradually applied in clinical practice. Iatrogenic infection caused by duodenoscopy is a well-documented complication, which has gained extensive attention especially in duodenoscope cleaning and disinfecting. It has been postulated that the complexity in design of duodenoscope makes cleaning difficult and poses a risk for nosocomial infections. As such, it is of positive practical significance to analyze the factors that affect cleaning and disinfecting and to take effective measures to do them better, in order to prevent nosocomial infection. This paper briefly reviews the cleaning and sterilizing of duodenoscope and the risk of infection associated with duodenoscopy.

Endoscope Reprocessing: Update on Controversial Issues

Several issues concerning endoscope reprocessing remain unresolved based on currently available data. Thus, further studies are required to confirm standard practices including safe endoscope shelf life, proper frequency of replacement of some accessories including water bottles and connecting tubes, and microbiological surveillance testing of endoscopes after reprocessing. The efficacy and cost-effectiveness of newer technology that allows automated cleaning and disinfection is one such controversial issue. In addition, there are no guidelines on whether delayed reprocessing and extended soaking may harm endoscope integrity or increase the bioburden on the external or internal device surfaces. In this review, we discuss the unresolved and controversial issues regarding endoscope reprocessing.

Infectious diseases linked to cross-contamination of flexible endoscopes

Flexible endoscopes are widely used to examine, diagnose, and treat medical disorders. While the risk of endoscopy-related transmission of infection is estimated to be very low, more health care-associated infections are related to contaminated endoscopes than to any other medical device. Flexible endoscopes can get highly contaminated with microorganisms, secretions and blood during use. The narrow lumens and multiple internal channels make the cleaning of flexible endoscopes a complex and difficult task. Despite the availability of international, national and local endoscope reprocessing guidelines, contamination and transmission of microorganisms continue to occur. These transmissions are mostly related to the use of defective equipment, endoscope reprocessing failures, and noncompliance with recommended guidelines. This article presents an overview of publications about case reports and outbreaks related to contamination of flexible endoscopes.

Increasing potential risks of contamination from repetitive use of endoscope

BACKGROUND

Medical devices inserted into the human body can be divided into single-use devices and reusable medical devices (RMDs) depending on the method of use. RMDs are applied to >1 patient, and users reprocess them prior to repeat use. Therefore, reprocessing of RMDs has become more difficult, and issues related to infection risk have become more prevalent.

METHODS

Research was performed to compare differences in surface alterations between not-aged (NA) samples and accelerated-aging (AA) samples. NA and AA samples were exposed to potential contaminants and treated with the same cleaning conditions. Then the residual contaminants were analyzed, and adhesion characteristics were investigated.

RESULTS

Significant differences between the 2 sample groups were observed in the pattern of physical surface alterations. Similar to the endoscope for clinical use, a deep crack was found in the surface of the AA sample. According to the binding affinity test, highly likely potential contaminants were found more frequently on AA samples.

CONCLUSION

The results suggest the necessity of limiting the duration of time that RMDs may be used, considering the potential risk of infection from repetitive use of RMDs, and also raised the possibility of applying this simulation model of AA. This methodology can be applied to various RMDs, including endoscopes.

Effectiveness of Flexible Gastrointestinal Endoscope Reprocessing

The practice of reprocessing endoscopes and its effectiveness was evaluated in 37 services. Contamination of at least 1 endoscope could be identified in 34 (91.6%) of 37 services. Bacteria, fungi, and/or mycobacteria were isolated from 84.6% (33/39) of the colonoscopes (110–32,000 colony-forming units [CFUs]/mL) and from 80.6% (50/62) of the gastroscopes (100–33,000 CFUs/mL). Not all services followed recommended guidelines. Therefore, patients who underwent gastrointestinal endoscopies were exposed to diverse pathogens.

Is peracetic acid suitable for the cleaning step of reprocessing flexible endoscopes?

The bioburden (blood, protein, pathogens and biofilm) on flexible endoscopes after use is often high and its removal is essential to allow effective disinfection, especially in the case of peracetic acid-based disinfectants, which are easily inactivated by organic material. Cleaning processes using conventional cleaners remove a variable but often sufficient amount of the bioburden. Some formulations based on peracetic acid are recommended by manufacturers for the cleaning step. We performed a systematic literature search and reviewed the available evidence to clarify the suitability of peracetic acid-based formulations for cleaning flexible endoscopes. A total of 243 studies were evaluated. No studies have yet demonstrated that peracetic acid-based cleaners are as effective as conventional cleaners. Some peracetic acid-based formulations have demonstrated some biofilm-cleaning effects and no biofilm-fixation potential, while others have a limited cleaning effect and a clear biofilm-fixation potential. All published data demonstrated a limited blood cleaning effect and a substantial blood and nerve tissue fixation potential of peracetic acid. No evidence-based guidelines on reprocessing flexible endoscopes currently recommend using cleaners containing peracetic acid, but some guidelines clearly recommend not using them because of their fixation potential. Evidence from some outbreaks, especially those involving highly multidrug-resistant gram-negative pathogens, indicated that disinfection using peracetic acid may be insufficient if the preceding cleaning step is not performed adequately. Based on this review we conclude that peracetic acid-based formulations should not be used for cleaning flexible endoscopes.

Analysis of a panel of rapidly growing mycobacteria for resistance to aldehyde-based disinfectants

After several accounts across the globe of mycobacteria outbreaks associated with medical procedures and aldehyde disinfectants resistance, we undertook an analysis of mycobacteria isolated from patients seen in a hospital in the United States between 1994 and 2008 to determine prevalence of resistance to aldehyde-based disinfectants. Out of the 117 clinical isolates screened, 6 isolates belonging to the emerging Mycobacterium abscessus group were found to display significant levels of resistance to glutaraldehyde and ortho-phthalaldehyde.

Residual bioburden in reprocessed side-view endoscopes used for endoscopic retrograde cholangiopancreatography (ERCP)

BACKGROUND AND STUDY AIM

Worldwide some endoscopy units routinely continue to use manual reprocessing techniques for disinfection of side-view endoscopes. The aim of this study was to evaluate the outcome quality of manual reprocessing techniques for removal and inactivation of the bioburden from side-view endoscopes used for endoscopic retrograde cholangiopancreatography (ERCP) in a tertiary referral endotherapy unit in Sri Lanka.

METHODS

102 samples obtained from two different flexible side-view endoscopes (Olympus TJF Q 180V and Olympus TJF 160 R) were tested for microbial growth. Three samples were collected each time; one swab from the tip before and another after manual reprocessing. The third sample was collected by flushing the working channel with sterile normal saline after manual reprocessing. Microorganisms were identified by culturing the samples.

RESULT

: After reprocessing, culture-positive rates were 20 % and 9 % for the samples obtained from the tip and the working channel of the side-view endoscopes, respectively. Klebsiella spp. and Candida spp. were found to be the commonest microorganisms in the samples from the tips and from the working channels, respectively, of the reprocessed side-view endoscopes.

CONCLUSION

There is a high culture-positive rate after reprocessing of the side-view endoscopes using the manual reprocessing procedure, despite strict adherence to the protocol for reprocessing.

Evaluation of detergents and contact time on biofilm removal from flexible endoscopes

BACKGROUND

The formation of endoscopic biofilm reduces the results of cleaning and disinfection and may increase nosocomial infection. This study aims to evaluate the effects of various detergents and different contact time on the removal of biofilm on flexible endoscopes based on an artificial biofilm model.

METHOD

Endoscopic biofilm model was established and treated with various detergents (detergent 1, Rapid Multi-Enzyme; detergent 2, Scopezime; and detergent 3, Intercept) for 3, 5, and 7 minutes. Escherichia coli viable counts and biofilm changes were measured by colony counting and electron microscopy scanning, respectively.

RESULTS

Statistical differences were observed between various detergents and the control group (P < .001) but not among the different contact time groups (3, 5, and 7 minutes, P > .05). Multiple comparisons showed that statistical differences in residual biofilm bacteria were observed between the detergents and the control (P < .001). Significant differences (P < .001) in residual biofilm bacteria existed between the 2 enzymatic detergents and the nonenzymatic detergent group, whereas no significant difference was observed between the 2 enzymatic detergents (P > .05). No crossover effect was observed between various detergent groups, contact time, and the control group (P > .05). Electron microscopy scanning revealed that, after various detergents and contact time of 3, 5, and 7 minutes, the residual biofilm in the enzymatic detergent group was significantly more than that of the nonenzymatic detergent group. No significant difference was observed among the groups with the same detergent and different contact time.

CONCLUSION

Significantly more biofilm bacteria and biofilms were found in the enzymatic detergent groups compared with the nonenzymatic detergent group, whereas no significant difference was observed among 3, 5, and 7 minutes groups.

The role of biofilms in reprocessing medical devices

Biofilms are communities of microorganisms within extracellular polymeric material attached to surfaces. Within a biofilm, cells have some protection from drying and other stress factors in their environment, including antimicrobial agents. In this article, the challenges to medical device reprocessing posed by biofilms are addressed. Biofilm formation on reusable medical device surfaces is a risk that can be controlled. By ensuring prompt device cleaning and reprocessing either by high-level disinfection or sterilization and proper drying, biofilms will not have a chance to form. Reusable medical devices like flexible endoscopes that are promptly cleaned and disinfected, rinsed and dried pose little risk to patients.

[Removing biofilm from a endoscopic: evaluation of disinfection methods currently used]

Laboratory experimental study that compared the effectiveness of five methods of disinfection for the removal of biofilm in gastrointestinal endoscopes. New transparent tubes of polytetrafluoroethylene (Teflon®) were used as specimens to simulate the channels of flexible endoscopes. After pre-cleaning the tubes were intentionally contaminated with Pseudomonas aeruginosa and subjected to disinfection methods. As a result, none removed 100% of these biofilms. What else physically removed biofilm was 2% glutaraldehyde in an automatic processor, probably justified by the double clean, since the equipment has this phase at the beginning of your cycle. The method less effective for removing plaque and other debris was the acidic electrolytic water. These results suggest that the cleaning is most striking in the removal of biofilms that disinfection of consecutive since glutaraldehyde disinfectant by machine is more efficient, it is a fastener organic waste.

Validation of adenosine triphosphate to audit manual cleaning of flexible endoscope channels

BACKGROUND

Compliance with cleaning of flexible endoscope channels cannot be verified using visual inspection. Adenosine triphosphate (ATP) has been suggested as a possible rapid cleaning monitor for flexible endoscope channels. There have not been published validation studies to specify the level of ATP that indicates inadequate cleaning has been achieved.

OBJECTIVE

The objective of this study was to validate the Clean-Trace (3M Inc, St. Paul, MN) ATP water test method for monitoring manual cleaning of flexible endoscopes.

METHODS

This was a simulated use study using a duodenoscope as the test device. Artificial test soil containing 10(6) colony-forming units of Pseudomonas aeruginosa and Enterococcus faecalis was used to perfuse all channels. The flush sample method for the suction-biopsy (L1) or air-water channel (L2) using 40 and 20 mLs sterile reverse osmosis water, respectively, was validated. Residuals of ATP, protein, hemoglobin, and bioburden were quantitated from channel samples taken from uncleaned, partially cleaned, and fully cleaned duodenoscopes. The benchmarks for clean were as follows: <6.4 μg/cm(2) protein, <2.2 μg/cm(2) hemoglobin, and <4-log10 colony-forming units/cm(2) bioburden.

RESULTS

The average ATP in clean channel samples was 27.7 RLUs and 154 RLUs for L1 and L2, respectively (<200 RLUs for all channels). The average protein, hemoglobin, and bioburden benchmarks were achieved if <200 RLUs were detected. If the channel sample was >200 RLUs, the residual organic and bioburden levels would exceed the acceptable benchmarks.

CONCLUSION

Our data validated that flexible endoscopes that have complete manual cleaning will have <200 RLUs by the Clean-Trace ATP test.

Swab culture monitoring of automated endoscope reprocessors after high-level disinfection

AIM: To conduct a bacterial culture study for monitoring decontamination of automated endoscope reprocessors (AERs) after high-level disinfection (HLD).

METHODS: From February 2006 to January 2011, authors conducted randomized consecutive sampling each month for 7 AERs. Authors collected a total of 420 swab cultures, including 300 cultures from 5 gastroscope AERs, and 120 cultures from 2 colonoscope AERs. Swab cultures were obtained from the residual water from the AERs after a full reprocessing cycle. Samples were cultured to test for aerobic bacteria, anaerobic bacteria, and mycobacterium tuberculosis.

RESULTS: The positive culture rate of the AERs was 2.0% (6/300) for gastroscope AERs and 0.8% (1/120) for colonoscope AERs. All the positive cultures, including 6 from gastroscope and 1 from colonoscope AERs, showed monofloral colonization. Of the gastroscope AER samples, 50% (3/6) were colonized by aerobic bacterial and 50% (3/6) by fungal contaminations.

CONCLUSION: A full reprocessing cycle of an AER with HLD is adequate for disinfection of the machine. Swab culture is a useful method for monitoring AER decontamination after each reprocessing cycle. Fungal contamination of AERs after reprocessing should also be kept in mind.

Establishing a clinically relevant bioburden benchmark: a quality indicator for adequate reprocessing and storage of flexible gastrointestinal endoscopes

BACKGROUND

Microbiological surveillance of patient-ready flexible endoscopes has been suggested as a tool for endoscope reprocessing quality assurance. However, a proper guideline defining the performance and the frequency of monitoring procedures and specifying how to interpret the results is lacking.

MATERIALS AND METHODS

All channels from the 20 flexible gastrointestinal endoscopes (5 gastroscopes, 9 colonoscopes, and 6 duodenoscopes) used at an endoscopy clinic were tested for the presence of bacteria and fungi early every Monday morning over a 7-month period.

RESULTS

Bacteria and fungi were detected in 5.7% of the 383 channels tested. Of the 141 scopes tested, 14.1% had detectable growth in at least 1 channel. No significant relationship was detected between the scope or channel type and detection of microorganisms. Over the 7 months of testing, 99.5% of scope channels consistently demonstrated <100 cfu/mL of microbial growth.

CONCLUSION

Based on our clinical findings, we recommend 100 cfu/mL as a reliable and routinely achievable cutoff for bioburden residuals in reprocessed endoscope channels. This cutoff is the same as the Canadian cutoff for dialysis water.

HBV and HCV serological markers in patients with the hepatosplenic form of mansonic schistosomiasis

CONTEXT

Blood transfusion is one of the major risk factors for the transmission of the hepatitis B (HBV) and C (HCV) viruses. However, there are no reports describing the endoscopic transmission of these viruses in patients with the hepatosplenic form of schistosomiasis.

OBJECTIVE

To estimate the prevalence of serological markers of HBV and HCV in patients with the hepatosplenic form of schistosomiasis and evaluate the possible risk factors associated with these infections.

METHODS

A cross-sectional study was conducted on 230 patients with hepatosplenic form of schistosomiasis who attended a university hospital in Recife, Northeastern Brazil, from February to August 2008. The patients answered a standardized questionnaire about risk factors. Serum samples were analyzed for anti-HBc total, anti-HBs, HBsAg, and anti-HCV using enzyme-linked immunosorbent assays. Univariate analysis and multiple logistic regression were performed.

RESULTS

The prevalence was 30% for anti-HBc total and/or HBsAg and 7.4% for anti-HCV. There was a higher frequency of the serological markers in females and in patients aged .50 years. A significant association was detected between the presence of anti-HCV and the receipt of six or more blood transfusions. There was no association of history and number of digestive endoscopies with the serological markers analyzed.

CONCLUSIONS

We observed a higher prevalence of serological markers for HBV and a lower prevalence of anti-HCV. Our results indicate that females and patients of an advanced age are the most affected categories and that patients that received multiple transfusions are at a higher probability of HCV infection.

Endoscope reprocessing using glutaraldehyde in endoscopy services of Goiânia, Brazil: a realidade em serviços de endoscopia de Goiânia, GO

CONTEXT

The endoscopic procedure safety depends on the use of an adequately reprocessed device which quality is related to each of its operational steps.

OBJECTIVE

To characterize the reprocessing of endoscopes using glutaraldehyde in endoscopy services

METHODS

Study was conducted by observing the reprocessing of 60 endoscopes from 20 medical practices of the municipality of Goiânia, GO, central area of Brazil.

RESULTS

This study showed failure in all reprocessing steps. The pre-washing was performed in 24 (40.0%) of the endoscope. In the cleaning steps, was identify the improper use of enzymatic detergent, and in 27 (45.0%) cases, the brushing of internal channels was not performed. All 60 endoscopes were submitted to this disinfectant. However, for 33 (55.0%) of the cases the internal channels was not filled. The total immersion of endoscope in the glutaraldehyde was not performed in 39 (65.0%) cases. The recommended minimum total immersion time for exposure to 2% glutaraldehyde solution was followed only for 12 (20.0%) endoscopes. There was no filter for water treatment used in the rinse of most endoscopes 54 (90.0%) and to dry the internal channels only 6 (10.0%) of them used compressed air. Adequate storing conditions were identified.

CONCLUSION

Considering the particularities of the endoscope and its reprocessing, it is imperative to establish protocols to ensure the quality of the disinfection and the prevention of cross-contamination.

EVOTECH endoscope cleaner and reprocessor (ECR) simulated-use and clinical-use evaluation of cleaning efficacy

BACKGROUND

The objective of this study was to perform simulated-use testing as well as a clinical study to assess the efficacy of the EVOTECH Endoscope Cleaner and Reprocessor (ECR) cleaning for flexible colonoscopes, duodenoscopes, gastroscopes and bronchoscopes. The main aim was to determine if the cleaning achieved using the ECR was at least equivalent to that achieved using optimal manual cleaning.

METHODS

Simulated-use testing consisted of inoculating all scope channels and two surface sites with Artificial Test Soil (ATS) containing 108 cfu/mL of Enterococcus faecalis, Pseudomonas aeruginosa and Candida albicans. Duodenoscopes, colonoscopes, and bronchoscopes (all Olympus endoscopes) were included in the simulated use testing. Each endoscope type was tested in triplicate and all channels and two surface sites were sampled for each scope. The clinical study evaluated patient-used duodenoscopes, bronchoscopes, colonoscopes, and gastroscopes (scopes used for emergency procedures were excluded) that had only a bedside flush prior to being processed in the ECR (i.e. no manual cleaning). There were 10 to 15 endoscopes evaluated post-cleaning and to ensure the entire ECR cycle was effective, 5 endoscopes were evaluated post-cleaning and post-high level disinfection. All channels and two external surface locations were sampled to evaluate the residual organic and microbial load. Effective cleaning of endoscope surfaces and channels was deemed to have been achieved if there was < 6.4 microg/cm2 of residual protein, < 1.8 microg/cm2 of residual hemoglobin and < 4 Log10 viable bacteria/cm2. Published data indicate that routine manual cleaning can achieve these endpoints so the ECR cleaning efficacy must meet or exceed these to establish that the ECR cleaning cycle could replace manual cleaning

RESULTS

In the clinical study 75 patient-used scopes were evaluated post cleaning and 98.8% of surfaces and 99.7% of lumens met or surpassed the cleaning endpoints set for protein, hemoglobin and bioburden residuals. In the simulated-use study 100% of the Olympus colonoscopes, duodenoscopes and bronchoscopes evaluated met or surpassed the cleaning endpoints set for protein, and bioburden residuals (hemoglobin was not evaluated).

CONCLUSIONS

The ECR cleaning cycle provides an effective automated approach that ensures surfaces and channels of flexible endoscopes are adequately cleaned after having only a bedside flush but no manual cleaning. It is crucial to note that endoscopes used for emergency procedures or where reprocessing is delayed for more than one hour MUST still be manually cleaned prior to placing them in the ECR.

HCV carriers with normal alanine aminotransferase levels: healthy persons or severely ill patients? Dealing with an everyday clinical problem

Approximately 30% of patients with chronic HCV infection show persistently normal ALT levels. Although formerly referred to as 'healthy' or 'asymptomatic' HCV carriers, and thus historically excluded from antiviral treatment, it has now become clear that the majority of these patients have some degree of histological liver damage that may be significant in up to 20% of patients and might progress toward a more severe degree of liver fibrosis. A significant proportion of patients (> or =20%) experience periods of increased serum ALT (flare) associated with enhanced disease progression. However, controversies still exist in clinical practice regarding the definition of 'persistent' ALT normality, the virological and histological features of these subjects, the need for liver biopsy, the role of non invasive tools for the assessment of liver fibrosis (transient hepatic elastography, fibroscan), and the natural history and optimal management of chronic hepatitis C with normal ALT. The advent of new therapeutic options (pegylated interferons plus ribavirin) has shifted treatment targets toward eradication of underlying infection, with therapy decision based on age, severity of disease and likelihood of response rather than on aminotransferase levels. This review does approach the main unresolved issues on this topic in the form of a dialog between a hepatologist and a patient with HCV infection but normal alanine aminotransferase levels, trying to give evidence-based answers to the more frequently asked questions from patients and their physicians.

Aldahol high-level disinfectant

BACKGROUND

Glutaraldehyde and ortho-phthalaldehyde (OPA) are widely used as the active ingredients of high level disinfectants for heat-sensitive, semicritical medical instruments. However, both of these chemicals have limitations in their spectrum of antimicrobial activity. Glutaraldehyde disinfectants are poorly mycobactericidal, and require impractically long exposure times to kill spore-forming bacteria. OPA disinfectants kill many types of mycobacteria in practical exposure times, but require 32 hours to pass the Association of Official Analytical Chemists (AOAC) sporicidal test, and do not claim to be sterilants. These could be serious limitations that contribute to the formation of biofilms in endoscopes, after which the endoscopes are difficult to disinfect. The objective of our research was to discover a disinfectant formulation, based on aldehydes, that killed mycobacteria and spore-forming bacteria in a practical exposure time and temperature.

METHODS

Solutions of glutaraldehyde or OPA were prepared with various concentrations of alcohols, sodium and potassium salts, chelating agents, and detergents at alkaline pH values, and tested against cultures of mycobacteria and spore-forming bacteria to find a formulation that would kill these bacteria in practical exposure times at 20 degrees C or 25 degrees C.

RESULTS

Concentrations of < or =20% w/w isopropanol and < or =8% potassium acetate in combination with < or =3.5% w/w glutaraldehyde at alkaline pH values killed 6 log(10) of mycobacteria within 10 minutes at 20 degrees C. Similar combinations killed 6 log(10) of Bacillus subtilis in suspension within 30 minutes at 25 degrees C, and B subtilis within 60 minutes at 20 degrees C. The sporicidal activity of OPA was not increased by combination with isopropanol and potassium acetate salts.

CONCLUSIONS

Aldahol high-level disinfectant (US FDA K041360), a formulation of 3.5% glutaraldehyde in combination with 20% w/w isopropanol and 8% potassium acetate, kills mycobacteria within 10 minutes at 20 degrees C and kills 6 log(10) of cultures of the spore-forming bacteria B subtilis within 60 minutes at 20 degrees C.