Reprocessing semicritical items: An overview and an update on the shift from HLD to sterilization for endoscopes

BACKGROUND

Semicritical medical devices are defined as items that come into contact with mucous membranes or nonintact skin (e.g., gastrointestinal endoscopes, endocavitary probes). Such medical devices require minimally high-level disinfection.

METHODS

Analyze the methods used to reprocess semicritical medical devices and identify methods and new technologies to reduce the risk of infection.

RESULTS

The reprocessing methods for semicritical medical devices is described as well as a shift from high-level disinfection to sterilization for lumened endoscopes.

CONCLUSIONS

Strict adherence to current guidelines and transition to sterilization for endoscopes is required as more outbreaks have been linked to inadequately disinfected endoscopes and other semicritical items than any other reusable medical devices.

Disinfection, sterilization and antisepsis: An overview

BACKGROUND

Each year in the United States there are approximately 100,000,000 outpatient/inpatient surgical procedures. Each of these procedures involves contact by a medical device or surgical instrument with a patient's sterile tissue and/or mucous membrane. A major risk of all such procedures is the introduction of infection.

METHODS

We searched published literature for articles on the use and effectiveness of disinfectants, sterilization methods and antiseptics.

RESULTS

The level of disinfection is dependent on the intended use of the object: critical (items that contact sterile tissue such as surgical instruments), semicritical (items that contact mucous membrane such as endoscopes), and noncritical (devices that contact only intact skin such as stethoscopes) items require sterilization, high-level disinfection and low-level disinfection, respectively. Cleaning must always precede high-level disinfection and sterilization. Antiseptics are essential to infection prevention as part of a hand hygiene program as well as other uses such as surgical hand antisepsis and pre-operative patient skin preparation.

CONCLUSIONS

When properly used, disinfection and sterilization can ensure the safe use of invasive and non-invasive medical devices. Cleaning should always precede high-level disinfection and sterilization. Strict adherence to current disinfection and sterilization guidelines is essential to prevent patient infections and exposures to infectious agents.

Contamination Rates in Duodenoscopes Reprocessed Using Enhanced Surveillance and Reprocessing Techniques: A Systematic Review and Meta-Analysis

Background/Aims

Multiple outbreaks of multidrug-resistant organisms have been reported worldwide due to contaminated duodenoscopes. In 2015, the United States Food and Drug Administration recommended the following supplemental enhanced surveillance and reprocessing techniques (ESRT) to improve duodenoscope disinfection: (1) microbiological culture, (2) ethylene oxide sterilization, (3) liquid chemical sterilant processing system, and (4) double high-level disinfection. A systematic review and meta-analysis was performed to assess the impact of ESRT on the contamination rates.

Methods

A thorough and systematic search was performed across several databases and conference proceedings from inception until January 2021, and all studies reporting the effectiveness of various ESRTs were identified. The pooled contamination rates of post-ESRT duodenoscopes were estimated using the random effects model.

Results

A total of seven studies using various ESRTs were incorporated in the analysis, which included a total of 9,084 post-ESRT duodenoscope cultures. The pooled contamination rate of the post-ESRT duodenoscope was 5% (95% confidence interval [CI]: 2.3%–10.8%, inconsistency index [I²]=97.97%). Pooled contamination rates for high-risk organisms were 0.8% (95% CI: 0.2%–2.7%, I²=94.96).

Conclusions

While ESRT may improve the disinfection process, a post-ESRT contamination rate of 5% is not negligible. Ongoing efforts to mitigate the rate of contamination by improving disinfection techniques and innovations in duodenoscope design to improve safety are warranted.

Flexible gastrointestinal endoscope processing challenges, current issues and future perspectives

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

'Secondary biofilms' could cause failure of peracetic acid high-level disinfection of endoscopes

INTRODUCTION

The reduced susceptibility of biofilms to disinfectants presents a challenge to the successful reprocessing of medical equipment. This study examined the effect of residual biomass remaining after previous disinfection with peracetic acid (PAA) on the tolerance of subsequent mature Pseudomonas aeruginosa biofilms to PAA. The effect of enzymatic degradation of specific components of the extracellular polymeric substance (EPS) of P. aeruginosa biofilm on the effectiveness of PAA disinfection was also evaluated.

METHODS

The susceptibility of biofilm grown on the biomass of PAA-killed biofilm to PAA was compared with the PAA susceptibility of biofilm grown in wells of a 24-well plate by evaluating their viability using the plate count assay. The effect of PAA on biofilm biomass was measured using crystal violet quantification of total biofilm biomass, while its effect on the polysaccharide and protein components of biofilm EPS was quantified using the phenol-sulphuric acid assay or Bradford assay, respectively. A confocal microscope was used to visualize the distribution of living and dead cells in biofilms grown on residual biofilm biomass.

FINDINGS

The presence of residual biomass from previously disinfected biofilms significantly enhanced the tolerance of subsequent biofilms. A 96-h-old 'secondary biofilm' formed on disinfected biomass survived PAA concentrations of 4000 ppm, which exceeds the concentrations used in practice for high-level disinfection.

CONCLUSION

These observations indicate that, under certain circumstances, recolonization of residual EPS can cause failure of disinfection of medical equipment such as endoscopes, and emphasizes the importance of cleaning endoscopes prior to disinfection.

Methods for Endoscope Reprocessing

Over the past 2 decades, in hospital centers worldwide, there have been numerous outbreaks of multidrug-resistant organisms that have since been attributed to endoscopic transmission of the infections between patients, primarily from duodenoscopes. These outbreaks have focused the attention of endoscope manufacturers, professional societies, and regulatory agencies on improving the reprocessing of these devices. The key steps in this process are point-of-use precleaning, leak testing, manual cleaning, high-level disinfection, and finally drying and storage. The promise of these initial efforts suggest that the aim of minimizing and ultimately eliminating events of endoscope-/duodenoscope-associated transmission of infectious organisms between patients can be achieved.

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.

Endoscope reprocessing: Comparison of drying effectiveness and microbial levels with an automated drying and storage cabinet with forced filtered air and a standard storage cabinet

BACKGROUND

Automated drying may help prevent endoscopically transmitted infections. We aimed to assess the efficacy of an automated drying and storage cabinet compared to a standard storage cabinet in achieving endoscope dryness postreprocessing and in reducing the risk of microbial growth.

METHODS

Drying times of bronchoscopes, colonoscopes, and duodenoscopes using 2 drying platforms (an automated drying and storage cabinet vs a standard storage cabinet) were measured using cobalt chloride paper. Drying assessments occurred at: 30 minutes, 1 hour, 2 hours, 3 hours, and 24 hours. A simple linear regression analysis compared rates of microbial growth after inoculation with Pseudomonas aeruginosa following high-level disinfection at: 0, 3 hours, 12 hours, 24 hours, and 48 hours.

RESULTS

Using the automated drying and storage cabinet, internal channels were dry at 1 hour and external surfaces at 3 hours in all endoscopes. With the standard storage cabinet, there was residual internal fluid at 24 hours, whereas external surfaces were dry at 24 hours. For bronchoscopes, colonoscopes, and duodenoscopes, the standard cabinet allowed for an average rate of colony forming unit growth of 8.1 × 10⁶ per hour, 8.3 × 10⁶ per hour, and 7.0 × 10⁷ per hour, respectively; the automated cabinet resulted in colony forming unit growth at an average rate of -28.4 per hour (P = .02), -38.5 per hour (P = .01), and -200.2 per hour (P = .02), respectively.

CONCLUSIONS

An automated cabinet is advantageous for rapid drying of endoscope surfaces and in reducing the risk of microbial growth postreprocessing.

Special problems associated with reprocessing instruments in outpatient care facilities: Physical spaces, education, infection preventionists, industry, reflections

The infection preventionists' (IPs') presence and intervention in outpatient facilities continues to lag behind the inpatient hospital IPs' presence. Additionally, in an outpatient world that is heavy on instrument reprocessing, IPs must be prepared to assess instrument reprocessing practices, including high-level disinfection and sterilization to keep our patients and staffs safe. This paper presents 3 problems associated with instrument reprocessing practices in health care facilities, with a special emphasis on outpatient facilities: physical space problems, training and education problems, and lack of IPs' presence. We offer solutions and mitigation strategies for these 3 problems. We also give some reflections on the current state of IP presence and responsibilities, and industry responsibilities, and we call for robust partnerships between IPs and the instrument reprocessing industry.

Practical toolkit for monitoring endoscope reprocessing effectiveness: Identification of viable bacteria on gastroscopes, colonoscopes, and bronchoscopes

BACKGROUND

Experts have recommended microbiologic surveillance by external reference laboratories for certain flexible endoscopes. There is currently insufficient evidence on the feasibility and utility of cultures. Researchers evaluated a preassembled toolkit for collecting and processing samples from endoscopes.

METHODS

A pilot study was performed in a large academic medical center. A toolkit was used to aseptically sample biopsy ports and suction/biopsy channels of 5 gastroscopes, 5 colonoscopes, and 5 bronchoscopes after full reprocessing. Blinded specimens were packaged and transported on icepacks to a reference laboratory that used standard methodologies for microbial cultures.

RESULTS

The laboratory detected bacteria in samples from 60% of patient-ready endoscopes, including gram-positive and gram-negative species. Viable microbes (<10 CFU) were recovered from 2 gastroscopes, 3 colonoscopes, and 4 bronchoscopes. Stenotrophomonas maltophilia and Delftia acidovorans were recovered from all 3 endoscope types. Subsequent environmental testing detected S maltophilia in the reprocessing rinse water.

CONCLUSIONS

A preassembled toolkit facilitated the aseptic collection of samples for culturing by a reference laboratory that detected viable microbes on fully reprocessed endoscopes. Speciation allowed identification of potential pathogens and a possible common contamination source, demonstrating that microbial cultures may have value even when colony counts are low.

Persistent contamination on colonoscopes and gastroscopes detected by biologic cultures and rapid indicators despite reprocessing performed in accordance with guidelines

BACKGROUND

Pathogens have been transmitted via flexible endoscopes that were reportedly reprocessed in accordance with guidelines.

METHODS

Researchers observed reprocessing activities to ensure guideline compliance in a large gastrointestinal endoscopy unit. Contamination was assessed immediately after bedside cleaning, manual cleaning, high-level disinfection, and overnight storage via visual inspection, aerobic cultures, and tests for adenosine triphosphate (ATP), protein, carbohydrate, and hemoglobin.

RESULTS

All colonoscopes and gastroscopes were reprocessed in accordance with guidelines during the study. Researchers collected and tested samples during 60 encounters with 15 endoscopes. Viable microbes were recovered from bedside-cleaned (92%), manually cleaned (46%), high-level disinfected (64%), and stored (9%) endoscopes. Rapid indicator tests detected contamination (protein, carbohydrate, hemoglobin, or ATP) above benchmarks on bedside-cleaned (100%), manually cleaned (92%), high-level disinfected (73%), and stored (82%) endoscopes. Visible residue was never observed on endoscopes, but it was often seen on materials used to sample endoscopes. Seven endoscopes underwent additional reprocessing in response to positive rapid indicators. Control endoscope channels were free of biologic residue and viable microbes.

CONCLUSION

Despite reprocessing in accordance with US guidelines, viable microbes and biologic debris persisted on clinically used gastrointestinal endoscopes, suggesting current reprocessing guidelines are not sufficient to ensure successful decontamination.

High-level disinfection of gastrointestinal endoscope reprocessing

High level disinfection (HLD) of the gastrointestinal (GI) endoscope is not simply a slogan, but rather is a form of experimental monitoring-based medicine. By definition, GI endoscopy is a semicritical medical device. Hence, such medical devices require major quality assurance for disinfection. And because many of these items are temperature sensitive, low-temperature chemical methods, such as liquid chemical germicide, must be used rather than steam sterilization. In summarizing guidelines for infection prevention and control for GI endoscopy, there are three important steps that must be highlighted: manual washing, HLD with automated endoscope reprocessor, and drying. Strict adherence to current guidelines is required because compared to any other medical device, the GI endoscope is associated with more outbreaks linked to inadequate cleaning or disinfecting during HLD. Both experimental evaluation on the surveillance bacterial cultures and in-use clinical results have shown that, the monitoring of the stringent processes to prevent and control infection is an essential component of the broader strategy to ensure the delivery of safe endoscopy services, because endoscope reprocessing is a multistep procedure involving numerous factors that can interfere with its efficacy. Based on our years of experience in the surveillance of culture monitoring of endoscopic reprocessing, we aim in this study to carefully describe what details require attention in the GI endoscopy disinfection and to share our experience so that patients can be provided with high quality and safe medical practices. Quality management encompasses all aspects of pre- and post-procedural care including the efficiency of the endoscopy unit and reprocessing area, as well as the endoscopic procedure itself.

Reported gastrointestinal endoscope reprocessing lapses: the tip of the iceberg

BACKGROUND

Most cases of microbial transmission to patients via contaminated endoscopes have resulted from nonadherence to reprocessing guidelines. We evaluated the occurrence, features, and implications of reprocessing lapses to gauge the nature and breadth of the problem in the context of widely available and accepted practice guidelines.

METHODS

We examined peer-reviewed and non-peer-reviewed literature to identify lapses reported in North America during 2005 to 2012 resulting in patient exposure to potentially contaminated gastrointestinal endoscopes.

RESULTS

Lapses occurred in various types of facilities and involved errors in all major steps of reprocessing. Each lapse continued for several months or years until the problem was discovered except for one that was described as a single incident. There were significant implications for patients, including notification and testing, microbial transmission, and increased morbidity and mortality. Only 1 reprocessing lapse was found in a peer-reviewed journal article, and other incidents were reported in governmental reports, legal documents, conference abstracts, and media reports.

CONCLUSION

Reprocessing lapses are an ongoing and widespread problem despite the existence of guidelines. Lack of publication in peer-reviewed literature contributes to the perception that lapses are rare and inconsequential. Reporting requirements and epidemiologic investigations are needed to develop better evidence-based policies and practices.

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.

Comparison on the Efficacy of Disinfectants Used in Automated Endoscope Reprocessors: PHMB-DBAC versus Orthophthalaldehyde

BACKGROUND/AIMS

Since endoscopes are reusable apparatus classified as semicritical item, thorough reprocessing to achieve high-level disinfection is of utmost importance to prevent spread of infection. To improve disinfection efficacy and safety, disinfectants and endoscope reprocessors are continuously evolving. This study aimed to compare the efficacy of the combination of polyhexamethylenebiguanide hydrochloride-alkyldimethylbenzylammonium chloride (PHMB-DBAC) and orthophthalaldehyde (OPA) used respectively in ultrasonographic cleaning incorporated automated endoscope reprocessors: COOLENDO (APEX Korea) or OER-A (Olympus Optical).

METHODS

A total of 86 flexible upper endoscopes were randomly reprocessed with either COOLENDO/PHMB-DBAC or OER-A/OPA. Culture samplings were done at two sites (endoscope tip and working channel) which were later incubated on blood agar plate. Bacterial colonies were counted and identified.

RESULTS

The culture-positive rate at the endoscope tip and working channel was 0% and 2.33% for COOLENDO/PHMB-DBAC and 4.65% and 0% for OER-A/OPA. Staphylococcus hominis was cultured from one endoscope reprocessed with COOLENDO/PHMB-DBAC and Pseudomonas putida was isolated from two endoscopes reprocessed with OER-A/OPA.

CONCLUSIONS

The reprocessing efficacy of COOLENDO/PHMB-DBAC was non-inferior to that of OER-A/OPA (p=0.032; confidence interval, -0.042 to 0.042). During the study period, significant side effect of PHMB-DBAC was not observed.