High-level disinfection of gastrointestinal endoscope reprocessing

Evaluation of plasma activated liquids for the elimination of mixed species biofilms within endoscopic working channels

The use of reusable flexible endoscopes has increased dramatically over the past decade, however despite improvements in endoscope reprocessing, the continued emergence of endoscopy-associated outbreaks as a result of multi-drug resistant bacteria has highlighted the need for a new approach to disinfection. Here, the use of plasma activated liquids (PALs) for the elimination of mixed species biofilm contamination within the working channels of endoscopes was evaluated. Cold atmospheric pressure plasma was used to chemically activate water and a commercially available pH buffered peracetic acid to create PALs. Polytetrafluoroethylene endoscope surrogate test pieces were contaminated with clinically relevant mixed species biofilms. The efficacy of PALs for the decontamination of narrow lumens was compared against the commercial disinfectant. Plasma activation was found to increase the antibiofilm capabilities of pH buffered peracetic acid by introducing reactive chemical species into the solution. Disinfection of endoscopic test pieces with plasma activated disinfectant (PAD) resulted in a 7.30 log10 reduction of biofilm contamination in 5 min, surpassing the 4.39 log10 reduction observed with the currently used endoscope disinfection method. PAD also resulted in reduced regrowth and recolonization of the surface of the endoscopic test pieces. Minimal changes to the surface morphology and composition were observed following exposure to PAD in comparison to the commercial disinfectant, suggesting the developed approach is no more aggressive than current disinfection approaches.

Effect of a disposable endoscope precleaning kit in the cleaning procedure of gastrointestinal endoscope: A multi-center observational study

BACKGROUND

Precleaning is a key step in endoscopic reprocessing.

AIM

To develop an effective and economic endoscope cleaning method by using a disposable endoscope bedside precleaning kit.

METHODS

Altogether, 228 used gastrointestinal endoscopes were selected from five high-volume endoscopy units and precleaned by a traditional precleaning bucket (group T) or a disposable endoscope bedside precleaning kit (group D). Each group was further subdivided based on the replacement frequency of the cleaning solution, which was replaced every time in subgroups T1 and D1 and every several times in subgroups Ts and Ds. The adenosine triphosphate (ATP) level and residual proteins were measured three times: Before and after precleaning and after manual cleaning.

RESULTS

After precleaning, the precleaning kit significantly reduced the ATP levels (P = 0.034) and has a more stable ATP clearance rate than the traditional precleaning bucket. The precleaning kit also saved a quarter of the cost of enzymatic detergent used during the precleaning process. After manual cleaning, the ATP levels were also significantly lower in the precleaning kit group than in the traditional precleaning bucket group (P < 0.05). Meanwhile, the number of uses of the cleaning solution (up to four times) has no significant impact on the cleaning effect (P > 0.05).

CONCLUSION

Considering its economic cost and cleaning effect, the use of a disposable endoscope bedside precleaning kit can be an optimal option in the precleaning stage with the cleaning solution being replaced several times in the manual cleaning stage.

Gastrointestinal Endoscopy-Associated Infections: Update on an Emerging Issue

Over 17.7 million gastrointestinal (GI) endoscopic procedures are performed annually, contributing to 68% of all endoscopic procedures in the United States. Usually, endoscopic procedures are low risk, but adverse events may occur, including cardiopulmonary complications, bleeding, perforation, pancreatitis, cholangitis, and infection. Infections after the GI endoscopies most commonly result from the patient's endogenous gut flora. Although many studies have reported infection after GI endoscopic procedures, a true estimate of the incidence rate of post-endoscopy infection is lacking. In addition, the infection profile and causative organisms have evolved over time. In recent times, multi-drug-resistant microorganisms have emerged as a cause of outbreaks of endoscope-associated infections (EAI). In addition, lapses in endoscope reprocessing have been reported, with some but not all outbreaks in recent times. This systematic review summarizes the demographical, clinical, and management data of EAI events reported in the literature. A total of 117 articles were included in the systematic review, with the majority reported from North America and Western Europe. The composite infection rate was calculated to be 0.2% following GI endoscopic procedures, 0.8% following ERCP, 0.123% following non-ERCP upper GI endoscopic procedures, and 0.073% following lower GI endoscopic procedures. Pseudomonas aeruginosa was the most common culprit organism, followed by other Enterobacteriaceae groups of organisms and Gram-positive cocci. We have also elaborated different prevention methods such as antimicrobial prophylaxis, adequate sterilization methods for reprocessing endoscopes, periodic surveillance, and current evidence supporting their utilization. Finally, we discuss disposable endoscopes, which could be an alternative to reprocessing to minimize the chances of EAIs with their effects on the environmental and financial situation.

An Analysis of the Effectiveness of High-level Disinfection for Surgical Instruments Used by Department of Defense Austere Surgical Teams

INTRODUCTION

The purpose of this investigation was to evaluate the efficacy of currently employed commercial disinfectants in a simulated austere surgical environment similarly faced by ground surgical teams in forward deployed positions. Severe contamination of traumatic combat wounds along with limitations of operations in austere environments may result in available disinfectants providing inadequate surgical instrument decontamination.

MATERIALS AND METHODS

The study consisted of nine experimental groups and two control groups evaluating hemostatic forceps found in kits of ground surgical teams. Hemostats were contaminated in a manner replicating the use in austere wartime surgery, cleaned by manual debridement and soaked in a disinfectant. Initially, instruments were debrided in one of three initial liquids (potable water, sterile water, or potable water with Envirocleanse A) and subsequently treated with one of three terminal disinfectants (Cidex OPA, CaviCide, or Neutral Disinfectant Cleaner). Treated hemostats were placed in sterile wire-closure bags for various storage times and tested for viable bacteria measured by colony-forming units.

RESULTS

Our findings indicated that mechanical debridement in water, independent of Envirocleanse A, followed by soaking in any of the three terminal disinfectants achieved a marked reduction in recovered bacteria from hemostats regardless of storage length. Of the three disinfectants tested, Cidex OPA appeared to be the most robust in terms of decontamination, followed by CaviCide and Neutral Disinfectant Cleaner.

CONCLUSIONS

This study supports the conclusion that all evaluated disinfectants are capable of rapidly producing instruments with minimal bacterial contaminants when standard sterilization is unavailable. Therefore, when lifesaving surgical intervention must be performed in a deployed environment, austere surgical teams can confidently utilize either product with minimal risk of infection. However, of the disinfectants, Cidex OPA appears to be most effective in reducing bacterial contamination for both rapid and slow turnover of instrument usage, and thus, the disinfectants are recommended for application when sterilization is not available.

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.

Is Post-Reprocessing Microbiological Surveillance of Duodenoscopes Effective in Reducing the Potential Risk in Transmitting Pathogens?

Background: The use of a contaminated endoscope may lead to infections due to the transmission of potential pathogens from patient to patient. Methods: Post-reprocessing microbiological surveillance of four duodenoscopes was carried out over a three-year period in the Digestive Endoscopy Unit of an Italian hospital. Sampling of duodenoscopes was performed after the devices have been reprocessed. The initial phase of surveillance involved the contemporary evaluation of the four duodenoscopes; afterwards, microbiological surveillance proceeded at monthly intervals. Results: The initial phase of surveillance revealed that three duodenoscopes presented a high level of contamination with “high-concern” micro-organisms, some of which were multi-drug-resistant. The highest values of contamination regarded the species P. aeruginosa (2500 CFU/duodenoscope), K. pneumoniae (2580 CFU/duodenoscope), and A. baumannii (2600 CFU/duodenoscope). Since the cultures were repeatedly positive on three successive occasions, the contaminated devices were sent to the manufacturer for evaluation. Audits were carried out with the personnel responsible for reprocessing, which was aimed to optimize the procedures used, and subsequently, only one case of non-conformity was found. Conclusions: Our study highlighted both the potential risk of transmitting pathogens through the use of duodenoscopes and the importance of implementing a well-structured system of microbiological surveillance and training programs, in order to reduce the risk of spreading retrograde cholangiopancreatography (ERCP)-associated infections.

Super-achromatic optical coherence tomography capsule for ultrahigh-resolution imaging of esophagus

Endoscopic optical coherence tomography (OCT) is a noninvasive technology allowing for imaging of tissue microanatomies of luminal organs in real time. Conventional endoscopic OCT operates at 1300 nm wavelength region with a suboptimal axial resolution limited to 8-20 μm. In this paper, we present the first ultrahigh-resolution tethered OCT capsule operating at 800 nm and offering about 3- to 4-fold improvement of axial resolution (plus enhanced imaging contrast). The capsule uses diffractive optics to manage chromatic aberration over a full ~200 nm spectral bandwidth centering around 830 nm, enabling to achieve super-achromaticity and an axial resolution of ~2.6 μm in air. The performance of the OCT capsule is demonstrated by volumetric imaging of swine esophagus ex vivo and sheep esophagus in vivo, where fine anatomic structures including the sub-epithelial layers are clearly identified. The ultrahigh resolution and excellent imaging contrast at 800 nm of the tethered capsule suggest the potential of the technology as an enabling tool for surveillance of early esophageal diseases on awake patients without the need for sedation.

Recent upper gastrointestinal panendoscopy increases the risk of pyogenic liver abscess

AIM

To investigate the association between a recent gastrointestinal (GI) endoscopy and the subsequent risk of pyogenic liver abscess (PLA).

METHODS

We designed a nested case control study. Using the Taiwan National Health Insurance Research Database, 2135 patients with a first diagnosis of PLA were identified from 1998 to 2011. Another 10675 patients without PLA matched by age and sex were selected as reference controls. We identified and compared the possible risk factors for PLA and GI endoscopies performed before the index date (when PLA was diagnosed) between the two cohorts. Multivariate analysis was conducted to examine the risk of PLA within the 90 d after the GI endoscopies.

RESULTS

Patients with a history of diabetes [adjusted odds ratio (aOR) = 4.92, 95%CI: 1.78-13.61], end-stage renal disease (aOR = 3.98, 95%CI: 1.45-10.91), biliary tract infection (aOR = 2.68, 95%CI: 2.11-3.40), liver cirrhosis (aOR = 2.19, 95%CI: 1.39-3.46), GI malignancies (aOR = 5.68, 95%CI: 4.23-7.64), appendicitis (aOR = 3.16, 95%CI: 2.27-4.41), diverticulitis (aOR = 1.64, 95%CI: 1.01-2.64), and recent endoscopic retrograde cholangiopancreatography (aOR = 27.04, 95%CI: 11.65-62.72) were significantly associated with an increased risk of PLA. After adjusting for the above risk factors and the frequency of outpatient department visits and abdominal ultrasounds during 90 d before the index date, an upper GI panendoscopy (aOR = 2.75, 95%CI: 2.05-3.69) but not a lower GI endoscopy (aOR = 1.07, 95%CI: 0.62-1.86) was significantly associated with PLA.

CONCLUSION

An upper GI panendoscopy performed before 90 d may increase the risk of PLA.

Role of Clinical Endoscopy in Emphasizing Endoscope Disinfection

Based on the unexpected Middle East respiratory syndrome (MERS) outbreak in Korea, it was established that the virus can spread easily, MERS exposure in hospitals carries an extreme risk for infection as well as mortality, and the sharing of information was essential for infection control. Although the incidence of exogenous infections related to contaminated endoscopes is very low, the majority of published outbreaks have been caused by various shortcomings in reprocessing procedures, including insufficient training or awareness. Ever since the inauguration of "Clinical Endoscopy" as an English-language journal of the Korean Society of Gastrointestinal Endoscopy in 2011, it has published several articles on disinfection of the endoscope and its accessories. Many Science Citation Index journals have also emphasized high-level disinfection of the gastrointestinal endoscope. Many papers have been produced specifically, since the outbreak of carbapenem-resistant Enterobacteriaceae in 2013. The recent review papers concluded that quality control is the most important issue among all the aspects of procedural care, including the efficiency of the gastrointestinal endoscopy unit and reprocessing room. Thorough reprocessing of endoscopes using high-level disinfection and sterilization methods may be essential for reducing the risk of infection.

Recent Update on Microbiological Monitoring of Gastrointestinal Endoscopes after High-Level Disinfection

Endoscopy-related infections are important contributors to nosocomial infections. Endoscope reprocessing according to standard guidelines ensures high-level disinfection and prevents endoscopy-related infections. Microbiological surveillance may help in monitoring the effectiveness of gastrointestinal endoscope disinfection. The process involves microbial cultures and non-culture methods such as bioburden assays, adenosine triphosphate (ATP) bioluminescence, and quantitative polymerase chain reactions (PCRs). Surveillance culturing to monitor endoscopes after reprocessing has been recommended by a majority of organizations. Bioburden assays, ATP bioluminescence, and quantitative PCRs provide rapid and reliable measures. Each institution will have to try to establish its own surveillance guidelines.