Society of Gastroenterology Nurses and Associates. Standards of infection control in reprocessing of flexible gastrointestinal endoscopes. Gastroenterol Nurs. 2013;36:293-303. [PMID: 23899491 DOI: 10.1097/SGA.0b013e31829c6d5b]

The Cost of Flexible Bronchoscopes: A Systematic Review and Meta-analysis

BACKGROUND AND OBJECTIVE

Until 2009, only reusable bronchoscopes were marketed, but the introduction and widespread adoption of single-use flexible bronchoscopes (SFBs) as an emerging technology has since accelerated. Several studies have described the costs of reusable flexible bronchoscopes (RFBs) and SFBs. This meta-analysis aimed to compile the current published evidence to analyse the cost of different scenarios using RFBs and SFBs.

METHODS

All published literature describing the cost of RFBs or SFBs was identified by searching PubMed, Embase and Google Scholar, limited to those between 1 January, 2009 and 6 November, 2020. Included studies should report the total cost of RFBs. Continuous data were extracted for relevant outcomes and analysed using RStudio^® 4.0.3 as the standardised mean difference and standard error of the mean in a mixed-effects model. Risk of bias was assessed based on the reporting quality.

RESULTS

In the systematic literature review, 342 studies were initially identified, and 11 were included in the final analysis. The mean RFB procedure cost was $266 (standard error of the mean: 34), including capital investments, repairs and reprocessing costs of $91, $92 and $83, respectively. The mean SFB procedure cost was $289 (standard error of the mean: 10). The incremental cost was $23 (standard error of the mean: 33) and was not significant (p = 0.46). Because of the economy of scale, RFB is more likely to be cost minimising compared with SFB when performing 306 or 39 procedures per site or RFB, respectively.

CONCLUSIONS

In this study, we found no significant difference in the cost of use between RFBs and SFBs and a high risk of bias.

Sans Standardization: Effective Endoscope Reprocessing

Bronchoscopy is a commonly performed procedure within thoracic and critical care medicine. Modern bronchoscopes are technologically advanced tools made of fragile electronic components. Their design is catered to allow maximum maneuverability within the semi-rigid tracheobronchial tree. Effective cleaning and reprocessing of these tools can be a challenge. Although highly functional, the design poses several challenges when it comes to reprocessing. It is a very important step, and lapses in the procedure have been tied to nosocomial infections. The process lacks universal standardization; several organizations have developed their own recommendations. Data have shown that key stakeholders are not fully versed in the essentials of endoscope reprocessing. A significant knowledge gap exists between those performing bronchoscopy and those who are stewards of effective endoscope reprocessing. To service as a resource for bronchoscopists, this study summarizes the steps of effective reprocessing, details the important elements within a health-care facility that houses this process, and reviews some of the current data regarding the use of disposable endoscopes.

The Effectiveness of Drying on Residual Droplets, Microorganisms, and Biofilms in Gastrointestinal Endoscope Reprocessing: A Systematic Review

BACKGROUND

Despite endoscope reprocessing, residual droplets remain in gastrointestinal endoscope working channels. Inadequate drying of gastrointestinal endoscope working channels may promote microbial reproduction and biofilm formation, increasing the risk of infection in patients. This review was designed to provide the current status of gastrointestinal endoscope drying, emphasize the importance of gastrointestinal endoscope drying, and evaluate the effectiveness of different drying methods of gastrointestinal endoscope in reducing residual droplets and microbial growth risk.

METHODS

A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting checklist. The PubMed, Web of Science, Medline, EMBASE, EBSCO, CNKI, CQVIP, and Wanfang Data databases were searched from 2010 to 2020 to identify eligible articles focused on methods of gastrointestinal endoscope drying and the status of endoscope drying. The following key points were analyzed: type of intervention, amount of residual droplets, major microbial types, and effectiveness of biofilm intervention. JBI quality assessment tool was used to determine bias risk for inclusion in the article.

RESULTS

This review included twelve articles. Two of the articles reported lack of drying of gastrointestinal endoscopes while the other ten reported residual droplets, microbial growth, and biofilm formation after different methods of drying. Four articles reported 0 to 4.55 residual droplets; four articles reported that the main microbial types were cocci and bacilli, most commonly Staphylococcus, Escherichia coli, Bacillus maltophilia, and Pseudomonas aeruginosa; and two reported that drying could effectively reduce biofilm regeneration. The type of intervention is as follows: automatic endoscopy reprocessor (AER), manual compressed air drying, and the Dri-Scope Aid for automatic drying and drying cabinet.

CONCLUSIONS

While endoscope reprocessing may not always be effective, an automatic endoscope reprocessor plus the Dri-Scope Aid with automatic drying over 10 min or storage in a drying cabinet for 72 h may be preferred.

Bioburden and transmission of pathogenic bacteria through elevator channel during endoscopic retrograde cholangiopancreatography: application of multiple-locus variable-number tandem-repeat analysis for characterization of clonal strains

OBJECTIVES

Endogenous and exogenous infection of the biliary tract could occur during endoscopic retrograde cholangiopancreatography.

METHODS

Bile samples of patients with hepatobiliary diseases, and swab samples of elevator channel samples of duodenoscope and washing instruments were prepared simultaneously and cultured aerobically and anaerobically. Antimicrobial susceptibility of the most common characterized bacterial species was tested, and their genetic relatedness was analyzed by multiple locus variable number of tandem repeats method.

RESULTS

Contamination with Pseudomonas aeruginosa was detected in 38.2% of the elevator channels' and 26.6% of the bile samples. Staphylococcus aureus, Enterococcus spp., Staphylococcus epidermidis, Escherichia coli, Enterobacter spp., and Clostridium perfringenes were among other bacterial isolates in the elevator channel swab samples. Highest antimicrobial resistance rate among P. aeruginosa isolates from the bile and swab samples were detected against gentamicin (100% and 73%, respectively), while the lowest one was measured to piperacillin-tazobactam (25% and 0%, respectively). Out of the 27 distinct MLVA profiles, relatedness of P. aeruginosa strains in the bile samples compared with those from the elevators was shown in three series of the samples.

CONCLUSION

Identity of P. aeruginosa strains among the bile and elevator channel samples showed possibility of cross-contamination among patients even at distinct time intervals. Expert opinion: Bacterial infection is considered as main complications of ERCP. Entry of bacteria into the biliary tract via contaminated device and its related instruments and their proliferation in this tissue could cause serious infections. To prevent this side effect, reprocessing of medical equipment via standard cleaning and disinfection procedures are needed. Our results showed incompliance of methods used for endoscope cleaning and disinfection procedure. Although host risk factors, such as sphincterotomy, could increase rate of infection with different types of bacteria, their ability for formation of biofilm and spore, which could help them to resist disinfectants and washing procedures seems to be main cause of persistent colonization and transmission among different patients. New standards for disinfection compared with currently used methods and use of materials to eliminate formation of bacterial microcolonies seem to be necessary to prevent cross-contamination.

Is the Stella™ 5L system an effective cold sterilization technique for needle-based confocal miniprobes?

BACKGROUND AND OBJECTIVE

Needle-based confocal laser endomicroscopy (nCLE) under endoscopic ultrasound guidance is a newly developed imaging technique for pancreatic lesions and lymph nodes, enabling a subcellular level of resolution. The confocal miniprobe is an invasive instrument designed to be reused up to 10 times. Therefore, a method that ensures the complete elimination of microbial contaminants on the device is necessary. We studied the bactericidal efficacy of the Stella™ system, which purports to achieve this objective.

MATERIALS AND METHODS

The surfaces of three nCLE miniprobes were contaminated with suspensions of Bacillus atrophaeus (ATCC9372). One probe was randomly selected to count the bacterial load on the surface. The other two probes were manually cleaned and rinsed. One probe was randomly selected to count bacteria on the surface, and the other probe was sterilized using the Stella™ 5L endoscopic sterilization system before obtaining the bacterial count. The process was repeated for 20 cycles to evaluate the microbicidal efficacy of the Stella™ 5L endoscopic sterilization system. These miniprobes were immersed in the Stella Fuse disinfectant for 72 h. After the 72 h of immersion, the weight loss of probes was determined using a high precision electronic scale to examine corrosion following disinfection. The change in image quality was evaluated by an endoscopist.

RESULTS

From an initial contamination level of 4.48 × 106 ± 1.57 × 106 cfu/mL on the surface of the probes, the bacterial count was reduced to 4.25 × 102 ± 1.95 × 102 cfu/mL after manual cleaning (including enzyme washing), and no microorganisms were recovered after 20 cycles with the Stella™ 5L system. The probe weights before and after 72 h of immersion were 45.769 (45.768-45.771) g and 45.762 (45.752-45.768) g, respectively. No change in image quality was observed.

CONCLUSION

This study shows that the Stella™ 5L system is capable of the complete elimination of microorganism contamination in a short period and avoids the toxicity of typical disinfectants. It is a safe, cheap, and efficient sterilization approach that provides a new option for nCLE miniprobe sterilization.

Guideline Implementation: Processing Flexible Endoscopes

The updated AORN "Guideline for processing flexible endoscopes" provides guidance to perioperative, endoscopy, and sterile processing personnel for processing all types of reusable flexible endoscopes and accessories in all procedural settings. This article focuses on key points of the guideline to help perioperative personnel safely and effectively process flexible endoscopes to prevent infection transmission. The key points address verification of manual cleaning, mechanical cleaning and processing, storage in a drying cabinet, determination of maximum storage time before reprocessing is needed, and considerations for implementing a microbiologic surveillance program. Perioperative RNs should review the complete guideline for additional information and for guidance when writing and updating policies and procedures.

Clinical Issues- March 2017

Using one flexible endoscope for an upper and lower gastrointestinal (GI) endoscopy procedure Key words: flexible endoscope, esophagogastroduodenoscopy, colonoscopy, enteroscope, risk assessment. Enhanced methods for processing flexible duodenoscopes Key words: flexible duodenoscopes, liquid chemical sterilization, ethylene oxide sterilization, low-temperature sterilization, risk assessment. Modification of the Spaulding classification Key words: Spaulding classification, critical items, semicritical items, mucous membranes, risk assessment. Flushing flexible endoscope lumens with alcohol Key words: flexible endoscopes, isopropyl alcohol, ethyl alcohol, fixative, risk assessment. Using chlorine dioxide wipes for nonchanneled flexible endoscopes Key words: nonchanneled flexible endoscopes, high-level disinfectant, chlorine dioxide, risk assessment.

Disposable Bronchoscope Model for Simulating Endoscopic Reprocessing and Surveillance Cultures

BACKGROUND Endoscope-associated infections are reported despite following proper reprocessing methods. Microbiological testing can confirm the adequacy of endoscope reprocessing. Multiple controversies related to the method and interpretation of microbiological testing cultures have arisen that make their routine performance a complex target. OBJECTIVE We conducted a pilot study using disposable bronchoscopes (DBs) to simulate different reprocessing times and soaking times and to compare high-level disinfection versus ethylene oxide sterilization. We also reviewed the time to reprocessing and duration of the procedures. METHODS Bronchoscopes were chosen because an alternative disposable scope is commercially available and because bronchoscopes are more prone to delays in processing. Disposable bronchoscopes were contaminated using a liquid bacterial suspension and were then incubated for 1-4 hours. Standard processing and high-level disinfection were performed on 36 endoscopes. Ethylene oxide sterilization was performed on 21 endoscopes. Endoscope cultures were performed using the standard "brush, flush, brush" technique. RESULTS After brushing was performed, a final water-flush culture procedure was the most effective method of detecting bacterial persistence on the disposable scopes. Klebsiella pneumoniae was the most commonly recovered organism after reprocessing. Ethylene oxide sterilization did not result in total elimination of viable bacteria. CONCLUSION Routine endoscopy cultures may be required to assess the adequacy of endoscopic processing. Infect Control Hosp Epidemiol 2017;38:136-142.

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.

Evaluation of the ability of different detergents and disinfectants to remove and kill organisms in traditional biofilm

BACKGROUND

The objective of this study was to assess the ability of different detergent and disinfectant combinations to eradicate bacteria in traditional biofilm.

METHODS

Enterococcus faecalis and Pseudomonas aeruginosa were used to develop biofilm over 8 days. The biofilm on each minimum biofilm eradication concentration peg contained 8 log₁₀ colony forming units (CFU)/cm² of both bacteria. The detergents evaluated were as follows: Prolystica Enzymatic 2X, Prolystica Neutral 2X, Neodisher, and Endozime Bio-Clean. The disinfectants evaluated were as follows: glutaraldehyde, accelerated hydrogen peroxide, and ortho-phthalaldehyde. Biofilm removal was evaluated using viable count, protein and carbohydrate quantitation, and scanning electron microscopy.

RESULTS

Only Prolystica Enzymatic 2X and Endozime Bio-Clean killed both E faecalis (3.90 log₁₀ CFU/mL reduction) and P aeruginosa (3.96 log₁₀ CFU/mL reduction) in suspension. None of the detergents tested could provide >1 log₁₀ CFU/cm² reduction for bacteria within biofilm. Any combination of detergent and high-level disinfectant reduced the level of both E faecalis and P aeruginosa within biofilm by 3-5 log₁₀ CFU/cm². Although the combination of Endozime Bio-Clean and glutaraldehyde provided a 6 log₁₀ reduction, it could not eliminate both bacteria within biofilm.

CONCLUSIONS

Our data indicate that if biofilm accumulates in flexible endoscope channels during repeated rounds of reprocessing, then neither the detergent nor high-level disinfectant will provide the expected level of bacterial removal or killing.

Disinfection and Sterilization in Health Care Facilities: An Overview and Current Issues

When properly used, disinfection and sterilization can ensure the safe use of invasive and noninvasive medical devices. The method of disinfection and sterilization depends on the intended use of the medical device: critical items (contact sterile tissue) must be sterilized before use; semicritical items (contact mucous membranes or nonintact skin) must be high-level disinfected; and noncritical items (contact intact skin) should receive low-level disinfection. Cleaning should always precede high-level disinfection and sterilization. Current disinfection and sterilization guidelines must be strictly followed.

Reprocessing semicritical items: Current issues and new technologies

Semicritical medical devices are defined as items that come into contact with mucous membranes or nonintact skin (eg, gastrointestinal endoscopes, endocavitary probes). Such medical devices minimally require high-level disinfection. Because many of these items are temperature sensitive, low-temperature chemical methods are usually used rather than steam sterilization. Strict adherence to current guidelines is required because more outbreaks have been linked to inadequately cleaned or disinfected endoscopes and other semicritical items undergoing high-level disinfection than any other reusable medical device.

Endoscope storage time: assessment of microbial colonization up to 21 days after reprocessing

BACKGROUND

Insufficient data exist for how long endoscopes can be stored after reprocessing. Concern about possible microbial colonization has led to various recommendations for reprocessing intervals among institutions, with many as short as 5 days. A significant cost savings could be realized if it can be demonstrated that endoscopes may be stored for as long as 21 days without risk of clinically significant contamination.

OBJECTIVE

To demonstrate whether flexible endoscopes may be stored for as long as 21 days after reprocessing without colonization by pathogenic microbes.

DESIGN

Prospective, observational study.

SETTING

Tertiary care center.

ENDOSCOPES

Four duodenoscopes, 4 colonoscopes, and 2 gastroscopes.

INTERVENTION

Microbial testing of endoscope channels.

MAIN OUTCOME MEASUREMENTS

Culture results at days 0, 7, 14, and 21.

RESULTS

There were 33 positive cultures from 28 of the 96 sites tested (29.2% overall contamination rate). Twenty-nine of 33 isolates were typical skin or environmental contaminants, thus clinically insignificant. Four potential pathogens were cultured, including Enterococcus, Candida parapsilosis, α-hemolytic Streptococcus, and Aureobasidium pullulans; all were likely clinically insignificant as each was only recovered at 1 time point at 1 site, and all grew in low concentrations. There were no definite pathogenic isolates.

LIMITATIONS

Single center.

CONCLUSION

Endoscopes can be stored for as long as 21 days after standard reprocessing with a low risk of pathogenic microbial colonization. Extension of reprocessing protocols to 21 days could effect significant cost savings.

Correlation between the growth of bacterial biofilm in flexible endoscopes and endoscope reprocessing methods

BACKGROUND

The purpose of this article was to investigate bacterial biofilm formed on endoscopes and to explore the possible correlation between endoscope reprocessing procedures and bacterial biofilm growth on endoscope channels.

METHODS

Sixty-six endoscope suction and biopsy channels and 13 water and air channels were collected from 66 hospitals throughout China. Scanning electron microscopy was used to observe biofilm growth on the internal surface of these channels. Questionnaires were mailed to 66 endoscopy centers to investigate reprocessing procedures for endoscopes.

RESULTS

Obvious biofilm growth was detected on 36 suction and biopsy channels (36/66, 54.6%) and 10 water and air channels (10/13, 76.9%). The percentage of manual cleaning in group B (n = 36, without detection of biofilms) was 92.3% (33/36), whereas it was 50.0% (15/30) in group A (n = 30, with detection of biofilms). Follow-up of group A (n = 30) showed that no biofilm was detected, whereas biofilm was detected in group B. The difference was statistically significant (P = .001). The proportion of detergent reuse in group B was 92.3% (33/36), and it was 61.5% in group A (18/30) (P = .005). The proportion of alcohol-air drying in group B was 38.9% (14/36), and it was 76.7% (23/30) in group A (P = .002).

CONCLUSION

The formation of endoscopic biofilm during clinical practice may be related to reuse of detergent, manual cleaning, and incomplete drying.

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.