Reprocessing endoscopes: United States perspective

The Effectiveness of Ultraviolet Smart D60 in Reducing Contamination of Flexible Fiberoptic Laryngoscopes

OBJECTIVE

To compare the effectiveness of disinfection protocols utilizing a ultraviolet (UV) Smart D60 light system with Impelux™ technology with a standard Cidex ortho-phthalaldehyde (OPA) disinfection protocol for cleaning flexible fiberoptic laryngoscopes (FFLs).

METHODS

Two hundred FFLs were tested for bacterial contamination after routine use, and another 200 FFLs were tested after disinfection with one of four methods: enzymatic detergent plus Cidex OPA (standard), enzymatic detergent plus UV Smart D60, microfiber cloth plus UV Smart D60, and nonsterile wipe plus UV Smart D60. Pre- and post-disinfection microbial burden levels and positive culture rates were compared using Kruskal-Wallis ANOVA and Fisher's two-sided exact, respectively.

RESULTS

After routine use, approximately 56% (112/200) of FFLs were contaminated, with an average contamination level of 9,973.7 ± 70,136.3 CFU/mL. The standard reprocessing method showed no positive cultures. The enzymatic plus UV, microfiber plus UV, and nonsterile wipe plus UV methods yielded contamination rates of 4% (2/50), 6% (3/50), and 12% (6/50), respectively, with no significant differences among the treatment groups (p > 0.05). The pre-disinfection microbial burden levels decreased significantly after each disinfection technique (p < 0.001). The average microbial burden recovered after enzymatic plus UV, microfiber plus UV, and nonsterile wipe plus UV were 0.40 CFU/mL ± 2, 0.60 CFU/mL ± 2.4, and 12.2 CFU/mL ± 69.5, respectively, with no significant difference among the treatment groups (p > 0.05). Micrococcus species (53.8%) were most frequently isolated, and no high-concern organisms were recovered.

CONCLUSION

Disinfection protocols utilizing UV Smart D60 were as effective as the standard chemical disinfection protocol using Cidex OPA.

LEVEL OF EVIDENCE

NA Laryngoscope, 133:3512-3519, 2023.

Evaluation of two detergent-disinfectants and a detergent on a Klebsiella pneumoniae biofilm formed within Tygon tubes

BACKGROUND

Transmission of infections via contaminated endoscopes is a common problem. Manual cleaning, using at least a detergent, is an important step in endoscope processing and should be performed as soon as possible to avoid drying of organic residues that might interfere with high-level disinfection and promote biofilm formation.

AIM

To assess the efficacy of two detergent-disinfectants, enzymatic and non-enzymatic, and of an enzymatic detergent used during the manual cleaning against a Klebsiella pneumoniae biofilm.

METHODS

A 24 h biofilm statically formed in a Tygon tube was exposed to detergent-disinfectants at 20 °C and 35 °C for 10 mn, and to enzymatic detergent at 45 °C for 60 mn. The logarithmic reduction in bacteria in the Tygon tube and the number of bacteria in the product supernatant were calculated.

FINDINGS

Biofilm formation was reproducible between assays. After exposure to detergent-disinfectants, the logarithmic reduction was between 6.32 and 6.71 log10 cfu/cm2 in the Tygon tubes. No bacteria were found in their supernatants. Results in the detergent-disinfectant group were not affected by the exposure temperature or the addition of enzymes. No decrease in the bacterial load was observed in the Tygon tubes after exposure to the enzymatic detergent. Bacteria were found in its supernatant.

CONCLUSION

These results show the importance of the choice of products used during the manual cleaning phase. They also show the potential benefit of combining detergent and disinfectant activity to decrease the bacterial load during the manual cleaning step of endoscope processing.

Economic analysis of the contribution of sialendoscopy in managing non-tumoral principal salivary gland pathology in the Réunion Island: Economic evaluation following the CHEERS methodology

GOALS

Cost analysis of the contribution of sialendoscopy in the treatment of non-tumoral pathologies of the main salivary glands, in Réunion Island, a French overseas territory.

OBJECTIVES

Calculation and comparison of median pricing (i.e., median payment to the healthcare establishment) per patient before and after the introduction of sialendoscopy, in the only regional establishment practicing sialendoscopy and in the whole of Réunion Island. Material and method A multicenter retrospective cost study was conducted over an 8-year period, before and after the introduction of sialendoscopy (period A: 2011-2014 and period B: 2015-2018), according to the CHEERS guidelines for economic studies, and included inpatients with non-tumoral pathology of the main salivary glands, whether treated by sialendoscopy or not.

RESULTS

Two hundred sixty-five patients were included, 139 of whom were treated by sialendoscopy: 74 in 2011-2014 and 191 in 2015-2018. Between the two periods, median pricing in the only center practicing sialendoscopy did not vary significantly: €3468 vs. €3368 (i.e., +2.9% (P=0.1)). In the Island as a whole, pricing increased significantly: €598 vs. €2332, (i.e., +390% (P<0.0001)).

CONCLUSION

Sialendoscopy is cost-effective in France in the public healthcare sector if outpatient management is optimal, but significantly increases the public health budget. It makes it possible to recruit and manage previously untreated patients (small stones, salivary strictures, etc.).

[Hygiene in ENT examination: Fluorescence study with overview of current recommendations]

Increasing normative demands on patient safety and quality assurance measures, but also the problem of multi-resistant germs and pathogens with a high potential for infection, increase the need for hygienically correct work.In this study, hygienically relevant potential sources of contamination in ENT examinations were to be identified and possible improvement strategies examined.A complete ENT examination was performed by 5 examiners with different professional experience, whose gloves were wetted with fluorescent lotion prior to the examination. Contaminations especially on the examination unit and on the instruments were identified. The potential risk of transmission of pathogens to subsequent patients was assessed using a specially developed score. Various strategies to reduce identified contamination possibilities were developed and thought through.The score of the investigators was very high with an average of 87.4 points (±3.6). The implementation of individual hygiene measures during the examination process would lead to a significant reduction of the score and thus to an improvement in hygiene: No shaking of hands (81.8), additional disinfection of patient's chair (79.8), disinfection of important surfaces (69.8), provision of standard instruments (60.2) or all instruments (32.2), disinfection of all relevant surfaces and provision of all instruments (7.4).The results show very clearly that an ENT examination is a complex procedure from the point of view of hygiene. For reliable protection against possible transmission events, a structured bundling of hygiene measures is therefore necessary.

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.

Novel and effective disposable device that provides 2-way protection to the duodenoscope from microbial contamination

BACKGROUND AND AIMS

Duodenoscope contamination is associated with notable patient morbidity and mortality and can occur despite high-level disinfection protocols, requiring a solution that protects against contamination of the endoscope in the first place.

METHODS

We assessed a newly cleared, single-use device to seal the distal end of duodenoscopes while preserving optics and other endoscope functionality and tested its ability to protect against contamination using dye immersion tests and microbial inoculation.

RESULTS

Dye immersion tests revealed a complete seal with no leakage. Rigorous microbial challenge tests showed the device can both protect against contamination of the endoscope by external microbes ("outside-in" protection) and shield instruments from contact with pre-existing microbial biofilm on or around the elevator that may have survived reprocessing ("inside-out" protection). Optical and mechanical performance of the endoscope was not compromised by the addition of the device.

CONCLUSIONS

The results show that this disposable device provides 2-way protection to the duodenoscope from microbial contamination, without the potential for disrupting current equipment, technique, and workflow.

Scan Parameter Optimization for Histotripsy Treatment of S. Aureus Biofilms on Surgical Mesh

There is a critical need to develop new noninvasive therapies to treat bacteria biofilms. Previous studies have demonstrated the effectiveness of cavitation-based ultrasound histotripsy to destroy these biofilms. In this study, the dependence of biofilm destruction on multiple scan parameters was assessed by conducting exposures at different scan speeds (0.3-1.4 beamwidths/s), step sizes (0.25-0.5 beamwidths), and the number of passes of the focus across the mesh (2-6). For each of the exposure conditions, the number of colony-forming units (CFUs) remaining on the mesh was quantified. A regression analysis was then conducted, revealing that the scan speed was the most critical parameter for biofilm destruction. Reducing the number of passes and the scan speed should allow for more efficient biofilm destruction in the future, reducing the treatment time.

Impact of High-Intensity Ultrasound on Strength of Surgical Mesh When Treating Biofilm Infections

The use of cavitation-based ultrasound histotripsy to treat infections on surgical mesh has shown great potential. However, any impact of the therapy on the mesh must be assessed before the therapy can be applied in the clinic. The goal of this study was to determine if the cavitation-based therapy would reduce the strength of the mesh thus compromising the functionality of the mesh. First, Staphylococcus aureus biofilms were grown on the surgical mesh samples and exposed to high-intensity ultrasound pulses. For each exposure, the effectiveness of the therapy was confirmed by counting the number of colony forming units (CFUs) on the mesh. Most of the exposed meshes had no CFUs with an average reduction of 5.4-log₁₀ relative to the sham exposures. To quantify the impact of the exposure on mesh strength, the force required to tear the mesh and the maximum mesh expansion before damage were quantified for control, sham, and exposed mesh samples. There was no statistical difference between the exposed and sham/control mesh samples in terms of ultimate tensile strength and corresponding mesh expansion. The only statistical difference was with respect to mesh orientation relative to the applied load. The tensile strength increased by 1.36 N while the expansion was reduced by 1.33 mm between different mesh orientations.

Histotripsy Treatment of S. Aureus Biofilms on Surgical Mesh Samples Under Varying Scan Parameters

Cavitation-based ultrasound histotripsy has shown potential for treating infections on surgical mesh. The goal of this paper was to explore a new scan strategy while assessing the impact of scan speed, scan step size, and the number of cycles in the tone burst on the destruction of S. aureus biofilms grown on surgical mesh samples using ultrasound histotripsy pulses (150 MPa/-17 MPa). For each exposure, the number of colony forming units (CFUs) on the mesh and released onto the surrounding gel was quantified. Most of the exposed mesh samples had no CFUs, and there was a statistically significant reduction in CFUs on the mesh for each of the exposures, with an average reduction of 3.8 log10 relative to the sham. Compared with the sham, there was also a statistically significant reduction in CFUs on the gel with the highest exposures.

Diagnosis of Helicobacter pylori Using Invasive and Noninvasive Approaches

Helicobacter pylori (H. pylori) as gram-negative and spiral microorganism is responsible for colonization in the gastric microniche for more than 50% of world population. Recent studies have shown a critical role of H. pylori in the development of peptic ulcers, gastric mucosa-associated lymphoid tissue (MALT) lymphoma, and gastric cancer. Over the past decade, there has been a sharp interest to use noninvasive tests in diagnosis of the H. pylori infection. During the years after discovery by Marshall and Warren, it has been frequently declared that the rapid urease test (RUT) is one of the cheapest and rapid diagnostic approaches used in detecting the infection. Although the specificity and sensitivity are durable for this test, clinical experiences had shown that the ideal results are only achieved only if we take biopsies from both corpus and antrum at the same time. Given the diagnosis of the H. pylori in clinical samples, gastroenterologists are facing a long list of various molecular and nonmolecular tests. We need more in-depth researches and investigations to correctly generalize rapid and accurate molecular tests determining both bacterial identity and antibiotic resistance profile.

Outbreaks associated with duodenoscopes: new challenges and controversies

PURPOSE OF REVIEW

Recent outbreaks of carbapenem-resistant enterobacteriaceae related to duodenoscopes in the United States and Europe have gained international attention and resulted in new regulations, especially in the United States, affecting healthcare facilities. In this review, we summarize findings from recent duodenoscope-related outbreaks, highlight what is known about the risk of transmission from these devices and discuss controversies about current recommendations to prevent transmission.

RECENT FINDINGS

Between 2013 and 2015, several US and European healthcare facilities reported outbreaks of carbapenem-resistant enterobacteriaceae associated with endoscopic retrograde cholangiopancreatography procedures. Unlike prior outbreaks (attributed to lapses in cleaning and reprocessing), the recent outbreaks occurred in spite of adherence to current reprocessing guidelines. Factors associated with infection transmission include a low margin of safety for gastrointestinal endoscopic procedures and complex design features of duodenoscopes. Outbreaks were halted with enhanced cleaning and surveillance measures or by adopting gas sterilization methods. New guidance from manufacturers and federal agencies has been issued as a result of these recent outbreaks; however, concerns remain that the new measures may not eliminate risks to patients.

SUMMARY

Recent duodenoscope-related outbreaks have highlighted the need for a reassessment of current guidelines for endoscope reprocessing and for new design of duodenoscope components. Although we summarize the US experience, this review has global implications for the safe cleaning and disinfection of these instruments.

Histotripsy Treatment of S. Aureus Biofilms on Surgical Mesh Samples Under Varying Pulse Durations

Prior studies demonstrated that histotripsy generated by high-intensity tone bursts to excite a bubble cloud adjacent to a medical implant can destroy the bacteria biofilm responsible for the infection. The goal of this paper was to treat Staphylococcus aureus (S. aureus) biofilms on surgical mesh samples while varying the number of cycles in the tone burst to minimize collateral tissue damage while maximizing therapy effectiveness. S. aureus biofilms were grown on 1-cm square surgical mesh samples. The biofilms were then treated in vitro using a spherically focused transducer (1.1 MHz, 12.9-cm focal length, 12.7-cm diameter) using either a sham exposure or histotripsy pulses with tone burst durations of 3, 5, or 10 cycles (pulse repetition frequency of 333 Hz, peak compressional pressure of 150 MPa, peak rarefactional pressure of 17 MPa). After treatment, the number of colony forming units (CFUs) on the mesh and the surrounding gel was independently determined. The number of CFUs remaining on the mesh for the sham exposure (4.8 ± 0.9-log₁₀) (sample mean ± sample standard deviation-log10 from 15 observations) was statistically significantly different from the 3-cycle (1.9 ± 1.5-log₁₀), 5-cycle (2.2 ± 1.1-log₁₀), and 10-cycle exposures (1 ± 1.5-log₁₀) with an average reduction in the number of CFUs of 3.1-log₁₀. The numbers of CFUs released into the gel for both the sham and exposure groups were the same within a bound of 0.86-log₁₀, but this interval was too large to deduce the fate of the bacteria in the biofilm following the treatment.

Experience With the Use of Single-Use Disposable Bronchoscope in the ICU in a Tertiary Referral Center of Singapore

BACKGROUND

Flexible bronchoscopy is performed frequently in intensive care units (ICUs) for various indications using the reusable conventional bronchoscope (CB). Recently, "single-use disposable bronchoscope" (SB) was introduced into the health care industry. The purpose of this study was to compare the utility of SB with CB in ICU.

METHODS

A retrospective review of medical records of patients undergoing flexible bronchoscopy in the ICUs in the year 2015.

RESULTS

Ninety-three patients undergoing flexible bronchoscopy in the ICU were studied. Eighty-three bronchoscopies were performed using SB in 71 patients, and 24 using CB in 22 patients. The most common indications for using the SB were percutaneous tracheostomy [n=37 (44.6%)] in neuro-ICU, followed by collecting specimens for microbiological evaluation [n=20 (24.1%)] in the medical ICU. Airway inspection [8 (9.6%)], bronchial toilet [8 (9.6%)], hemoptysis [5 (6%)], and intubation [3 (3.6%)] were other indications for which SB was used. Microbiological yield of SB was 70% (14/20) versus 70% (7/10) for CB (P=1.0). The median interval between identification of the need-to-start of the procedure was shorter with SB (10 min) versus CB (66 min, P=0.01), whereas the cost was similar, SGD450 versus SGD472, respectively. In addition, less (3 personnel) were needed to perform bronchoscopy with SB versus 5 with CB with additional resource sparing effect in terms of nursing personnel having to wheel the CB equipment to ICU.

CONCLUSIONS

SB is equivalent in performance to CB in ICU. In addition, the SB may confer clinical, economic, and logistical advantages over the CB.

Acute Glutaraldehyde Mucosal Injury of the Upper Aerodigestive Tract Due to Damage to the Working Channel of an Endoscope

Objectives

Glutaraldehyde (Cidex) is a commonly used agent for cold sterilization of endoscopes despite its known irritative, allergic, and carcinogenic potential. This report details the clinical course of 2 patients who suffered acute glutaraldehyde exposure during office injection procedures.

Methods

Clinical records of 2 outpatients undergoing office injection procedures were reviewed. One patient underwent bilateral injections of hydroxyapatite, and 1 underwent voice gel injection.

Results

Both patients developed acute mucosal injury in the form of supraglottitis and laryngitis. Both patients required inpatient admission with airway monitoring (1 requiring admission to the intensive care unit) and were treated with steroids and antibiotics. The same channel endoscope was used for both procedures and was noted after careful examination to have retained glutaraldehyde inside the scope due to a perforation of the lining of the working channel.

Conclusions

Glutaraldehyde can cause acute mucosal injury to supraglottic and glottic structures, and diligent procedures must be maintained for flushing the channels and monitoring glutaraldehyde retention in the channels. Great care should be taken to avoid damage to the lining of working channels from instrumentation.

Prospective microbiologic evaluation of the forceps elevator in closed-channel duodenoscopes after reprocessing

BACKGROUND

Endoscopes are well-known sources of bacterial transmission in health care facilities offering endoscopy services. The association between multidrug-resistant bacterial infections in patients who had undergone an endoscopic retrograde cholangiopancreatography procedure with reprocessed duodenoscopes has been much discussed. Bacterial contamination of duodenoscopes has been attributed to difficulties with reprocessing these devices, specifically the distal end of the scope, which features a movable forceps elevator. In light of a recent Food and Drug Administration warning letter to Olympus regarding their closed-channel duodenoscope model TJF-Q180V, the aim of our study was to prospectively evaluate the efficacy and safety of our current reprocessing procedures with regard to the TJF-Q180V duodenoscope models used in our hospital.

METHODS

From August 2015-March 2016, we prospectively collected microbiologic surveillance samples from 6 TJF-Q180V model duodenoscopes in routine use at the Division of Gastroenterology and Hepatology using the ESwab collection system (COPAN Diagnostics Inc, Murrieta, CA).

RESULTS

A total of 237 microbiologic samples from the forceps elevator were obtained during the survey period. None of the samples yielded microorganism growth.

CONCLUSION

These findings suggest that when following a diligent and validated reprocessing standard in accordance with manufacturer's recommendations, closed-channel endoscope models can still be used. Nevertheless, validated adaptions of current closed-channel duodenoscope models are needed to allow for simple and safe reprocessing. Furthermore, comprehensive postmarket surveillance needs to be established.

Is a chlorine dioxide wiping procedure suitable for the high-level disinfection of nasendoscopes?

BACKGROUND

Nasendoscopes are widely used in the outpatient ENT setting. Their reprocessing requires high-level disinfection (HLD). Recently, a wiping procedure using chlorine dioxide (ClO₂) has been proposed as an alternative to HLD traditional procedures.

OBJECTIVE

To assess the effectiveness of the HLD wiping procedure versus soaking procedure on a contaminated nasendoscope.

METHOD

A nasendoscope was contaminated with four strains of bacteria and Bacillus subtilis spores. After HLD either with the wiping procedure or with the soaking procedure (PA), the reduction of the initial contamination was determined.

FINDINGS

The wiping procedure with ClO₂ displayed more than 5 log reduction for vegetative bacteria after 30 s contact time (CT) and 4 log reduction on B. subtilis spores after 2 min CT. The soaking procedure with PA displayed similar results on planktonic bacteria after 10 min CT but the log reduction of B. subtilis remained below 4.

CONCLUSION

The ClO₂ wiping procedure showed bactericidal and sporicidal efficacy on a contaminated nasendoscope in a shorter time compared to the PA soaking procedure. Thus, ClO₂ wiping procedure might be considered as an alternative to the traditional HLD procedure for nasendoscopes.

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.

Principles of infection prevention and reprocessing in ENT endoscopy

This article gives an overview on the principles of reprocessing of rigid and flexible endoscopes used in ENT units including structural and spatial requirements based on general and ENT-specific risks of infection associated with diagnostic and therapeutic endoscopy. The underlying legal principles as well as recommendations from scientific societies will be exemplified in order to give a practical guidance to the otorhinolaryngologist. Preliminary results of a small nation-wide survey on infection control standards based on data of 29 ENT practices in Germany reveal current deficits of varying degree concerning infection control management including reprocessing of endoscopes. The presented review aims to give support to the establishment of a structured infection control management program including the evaluation of results by means of a prospective surveillance.

[Disinfection and recontamination of rigid endoscopes: improved safety using an immersion quiver system]

BACKGROUND

In Otorhinolaryngology, rigid endoscopes are used daily at a high frequency. There is no consensus for reprocessing these medical instruments. Often immersion disinfection procedures are used. The present study examined the possible risk of recontamination by this disinfection method and investigated the possibility of avoiding this risk by using a new immersion quiver system.

METHODS

Using coloured markers, a possible contact of the endoscope with the top edges of quivers of different diameters during endoscope removal was tested for. In addition, it was evaluated whether Staphylococcus aureus transfer is possible via this route. The same methodology was applied to a new immersion quiver system.

RESULTS

Whenever removing the rigid endoscopes from the conventional quiver, these touched the top of the quiver, regardless of its diameter. A transfer of Staphylococcus aureus from the quiver to the endoscope via this route could be detected in five out of eight attempts. During endoscope removal from the new immersion quiver system, no contact of the endoscope with the outer quiver occurred in 20 passes. In none of eight trials was a transfer of Staphylococcus aureus from previously contaminated immersion quivers to the endoscope shown; all immersion quivers were sterile after disinfection.

DISCUSSION

After conventional immersion disinfection, recontamination of rigid endoscopes by a contaminated quiver edge is possible. An immersion quiver system can resolve this risk of recontamination easily, by decontaminating not only the endoscope, but also the immersion quiver (inner quiver) itself in the disinfectant solution.

Microbiologic Surveillance of Duodenoscope Reprocessing at the Vienna University Hospital From November 2004 Through March 2015

Bacterial contamination of duodenoscopes is attributed to difficulties with reprocessing the Albarran lever. Routine microbiologic surveillance data of endoscopes with Albarran lever retrospectively collected from November 2004 through March 2015 revealed no growth of microorganism at this specific site. Transmission of endoscope-associated infection is avoidable by following validated reprocessing procedures.

Infect Control Hosp Epidemiol 2015;36(10):1233–1235

Results from a Large-Scale Epidemiologic Look-Back Investigation of Improperly Reprocessed Endoscopy Equipment

Objective.

To determine whether improper high-level disinfection practices during endoscopy procedures resulted in bloodborne viral infection transmission.

Design.

Retrospective cohort study.

Setting.

Four Veterans Affairs medical centers (VAMCs).

Patients.

Veterans who underwent colonoscopy and laryngoscopy (ear, nose, and throat [ENT]) procedures from 2003 to 2009.

Methods.

Patients were identified through electronic health record searches and serotested for human immunodeficiency virus (HIV), hepatitis C virus (HCV), and hepatitis B virus (HBV). Newly discovered case patients were linked to a potential source with known identical infection, whose procedure occurred no more than 1 day prior to the case patient's procedure. Viral genetic testing was performed for case/proximate pairs to determine relatedness.

Results.

Of 10,737 veterans who underwent endoscopy at 4 VAMCs, 9,879 patients agreed to viral testing. Of these, 90 patients were newly diagnosed with 1 or more viral bloodborne pathogens (BBPs). There were no case/proximate pairings found for patients with either HIV or HBV; 24 HCV case/proximate pairings were found, of which 7 case patients and 8 proximate patients had sufficient viral load for further genetic testing. Only 2 of these cases, both of whom underwent laryngoscopy, and their 4 proximates agreed to further testing. None of the 4 remaining proximate patients who underwent colonoscopy agreed to further testing. Mean genetic distance between the 2 case patients and 4 proximate patients ranged from 13.5% to 19.1%.

Conclusions.

Our investigation revealed that exposure to improperly reprocessed ENT endoscopes did not result in viral transmission in those patients who had viral genetic analysis performed. Any potential transmission of BBPs from colonoscopy remains unknown.

Results from a Large-Scale Epidemiologic Look-Back Investigation of Improperly Reprocessed Endoscopy Equipment

Objective.

To determine whether improper high-level disinfection practices during endoscopy procedures resulted in bloodborne viral infection transmission.

Design.

Retrospective cohort study.

Setting.

Four Veterans Affairs medical centers (VAMCs).

Patients.

Veterans who underwent colonoscopy and laryngoscopy (ear, nose, and throat [ENT]) procedures from 2003 to 2009.

Methods.

Patients were identified through electronic health record searches and serotested for human immunodeficiency virus (HIV), hepatitis C virus (HCV), and hepatitis B virus (HBV). Newly discovered case patients were linked to a potential source with known identical infection, whose procedure occurred no more than 1 day prior to the case patient's procedure. Viral genetic testing was performed for case/proximate pairs to determine relatedness.

Results.

Of 10,737 veterans who underwent endoscopy at 4 VAMCs, 9,879 patients agreed to viral testing. Of these, 90 patients were newly diagnosed with 1 or more viral bloodborne pathogens (BBPs). There were no case/proximate pairings found for patients with either HIV or HBV; 24 HCV case/proximate pairings were found, of which 7 case patients and 8 proximate patients had sufficient viral load for further genetic testing. Only 2 of these cases, both of whom underwent laryngoscopy, and their 4 proximates agreed to further testing. None of the 4 remaining proximate patients who underwent colonoscopy agreed to further testing. Mean genetic distance between the 2 case patients and 4 proximate patients ranged from 13.5% to 19.1%.

Conclusions.

Our investigation revealed that exposure to improperly reprocessed ENT endoscopes did not result in viral transmission in those patients who had viral genetic analysis performed. Any potential transmission of BBPs from colonoscopy remains unknown.

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.

Comparison of clinically relevant benchmarks and channel sampling methods used to assess manual cleaning compliance for flexible gastrointestinal endoscopes

BACKGROUND

The objectives of this study were to recommend sample collection method(s) based on relative soiling in patient-used gastrointestinal (GI) endoscopes and determine whether the published benchmarks for protein, bioburden, and adenosine triphosphate (ATP) remain relevant for pump-assisted manual cleaning.

METHODS

Patient-used gastroscopes, duodenoscopes, and colonoscopes were sampled before and after manual cleaning and assessed for protein, bioburden, and ATP levels. The biopsy port (BP) to distal end (D) sample was collected using 20 mL of sterile reverse-osmosis water. After a 200-mL flush, the umbilical (UM) to BP portion was sampled by flushing 40 mL from the UM to the D.

RESULTS

The BP to D portion of the suction biopsy channel contained 83% of ATP residuals. Despite cleaning with brushing and a flushing pump, 25% of gastroscopes exceeded the ATP benchmark of 200 relative light units (RLU), whereas all duodenoscopes and colonoscopes had <200 RLU after cleaning. The protein and bioburden residuals after pump-assisted cleaning were consistently lower than existing benchmarks.

CONCLUSION

Sampling the suction biopsy channel from BP to D detected the most residuals from patient-used GI endoscopes. The protein and bioburden benchmarks for pump-assisted cleaning can be lowered, but 200 RLU is still adequate for ATP.

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.

New developments in reprocessing semicritical items

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

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.

The adenosine triphosphate test is a rapid and reliable audit tool to assess manual cleaning adequacy of flexible endoscope channels

BACKGROUND

The study objective was to verify that the adenosine triphosphate (ATP) benchmark of <200 relative light units (RLUs) was achievable in a busy endoscopy clinic that followed the manufacturer's manual cleaning instructions.

METHODS

All channels from patient-used colonoscopes (20) and duodenoscopes (20) in a tertiary care hospital endoscopy clinic were sampled after manual cleaning and tested for residual ATP. The ATP test benchmark for adequate manual cleaning was set at <200 RLUs. The benchmark for protein was <6.4 μg/cm(2), and, for bioburden, it was <4-log10 colony-forming units/cm(2).

RESULTS

Our data demonstrated that 96% (115/120) of channels from 20 colonoscopes and 20 duodenoscopes evaluated met the ATP benchmark of <200 RLUs. The 5 channels that exceeded 200 RLUs were all elevator guide-wire channels. All 120 of the manually cleaned endoscopes tested had protein and bioburden levels that were compliant with accepted benchmarks for manual cleaning for suction-biopsy, air-water, and auxiliary water channels.

CONCLUSION

Our data confirmed that, by following the endoscope manufacturer's manual cleaning recommendations, 96% of channels in gastrointestinal endoscopes would have <200 RLUs for the ATP test kit evaluated and would meet the accepted clean benchmarks for protein and bioburden.

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.

Comparison of adenosine triphosphate, microbiological load, and residual protein as indicators for assessing the cleanliness of flexible gastrointestinal endoscopes

BACKGROUND

This study evaluated 3 potential indicators of gastrointestinal endoscope cleanliness: adenosine triphosphate (ATP), microbiological load, and protein.

METHODS

Before and after cleaning, ATP and microbiological load were determined from swabs of exterior surfaces and rinses of interior suction/accessory channels. Similarly, before and after cleaning, residual protein was determined from rinses of interior suction/accessory channels.

RESULTS

Before cleaning, ATP values were 10,417 relative light units (RLU) from the exterior endoscope surface and 30,281 RLU from the suction/accessory channel rinsates. After cleaning, these ATP values were decreased to 82 RLUs and 104 RLUs, a statistically significant difference. A similar trend was observed with microbiological load, but the change in residual protein from before cleaning to after cleaning was not significant. ATP values reliably reflected microbiological colony counts.

CONCLUSIONS

ATP measurement can provide a reliable, rapid and practical assessment of endoscope cleanliness for routine monitoring in the clinical setting.

Biofilms of a Bacillus subtilis hospital isolate protect Staphylococcus aureus from biocide action

The development of a biofilm constitutes a survival strategy by providing bacteria a protective environment safe from stresses such as microbicide action and can thus lead to important health-care problems. In this study, biofilm resistance of a Bacillus subtilis strain (called hereafter ND_medical) recently isolated from endoscope washer-disinfectors to peracetic acid was investigated and its ability to protect the pathogen Staphylococcus aureus in mixed biofilms was evaluated. Biocide action within Bacillus subtilis biofilms was visualised in real time using a non-invasive 4D confocal imaging method. The resistance of single species and mixed biofilms to peracetic acid was quantified using standard plate counting methods and their architecture was explored using confocal imaging and electronic microscopy. The results showed that the ND_medical strain demonstrates the ability to make very large amount of biofilm together with hyper-resistance to the concentration of PAA used in many formulations (3500 ppm). Evidences strongly suggest that the enhanced resistance of the ND_medical strain was related to the specific three-dimensional structure of the biofilm and the large amount of the extracellular matrix produced which can hinder the penetration of peracetic acid. When grown in mixed biofilm with Staphylococcus aureus, the ND_medical strain demonstrated the ability to protect the pathogen from PAA action, thus enabling its persistence in the environment. This work points out the ability of bacteria to adapt to an extremely hostile environment, and the necessity of considering multi-organism ecosystems instead of single species model to decipher the mechanisms of biofilm resistance to antimicrobials agents.

String capsule endoscopy for screening and surveillance of esophageal varices in patients with cirrhosis

BACKGROUND

EGD is the gold standard for the screening and surveillance of esophageal varices. A less invasive, safer and sedationless alternative procedure is needed.

OBJECTIVE

To assess the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) as well as the beyond the chance agreement (kappa index), of string capsule endoscopy (SCE) in the diagnosis of esophageal varices.

METHODS

Cirrhotic patients underwent string capsule endoscopy (SCE) and EGD for screening and surveillance purposes. Varices were graded at EGD and SCE as small, medium and large. Descriptors at SCE were added as follows: PLUS, for the presence of red wale signs or, MINUS for their absence, irrespective of the estimated variceal size. Clinically significant varices were defined by their size (medium/large at either EGD or SCE) and/or, the PLUS descriptor irrespective of the estimated size at SCE. Sensitivity, specificity, PPV, NPV, accuracy and kappa index were calculated. Procedure time, procedure-related discomfort and patient's preference were documented.

RESULTS

100 patients (33 for screening and 67 for surveillance) were enrolled. The sensitivity and specificity of SCE for clinically significant varices when using the PLUS/MINUS descriptors were 82% and 90%, respectively with a PPV of 84% and NPV of 89% and a kappa of 0.73.

CONCLUSION

String capsule endoscopy had an acceptable sensitivity and specificity for the diagnosis of clinically significant esophageal varices but the lack of air insufflation still hampers its correlation with the grading used with EGD.

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.

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.