Contribution of usage to endoscope working channel damage and bacterial contamination

Effect of a novel endoscope cleaning brush on duodenoscope contamination

BACKGROUND

Current duodenoscope reprocessing protocols are insufficient to prevent contamination and require adaptations to prevent endoscopy-associated infections (EAIs). This study aimed to investigate the effect of a new endoscope cleaning brush on the contamination rate of ready-to-use duodenoscopes.

METHODS

This retrospective before-and-after intervention study collected duodenoscope surveillance culture results from March 2018 to June 2022. Contamination was defined as ≥1 colony-forming unit of a microorganism of gut or oral origin (MGO). In December 2020, an endoscope cleaning brush with a sweeper design was introduced as an intervention in the manual cleaning of duodenoscopes. A logistic mixed-effects model was used to study the effects of this intervention.

RESULTS

Data were collected from 176 culture sets before the new brush's introduction and 81 culture sets afterwards. Pre-introduction, culture sets positive with an MGO comprised 45.5% (95%CI 38.3%-52.8%; 80/176), decreasing to 17.3% (95%CI 10.6%-26.9%; 14/81) after implementation of the new brush. Compared with the former brush, duodenoscopes cleaned with the new brush had lower odds of contamination with MGOs (adjusted odds ratio 0.25, 95%CI 0.11-0.58; P=0.001) CONCLUSIONS: Use of the new brush in manual cleaning reduced contamination with MGOs and is expected to prevent EAIs. These findings should be confirmed in future prospective randomized studies.

What Are the Ready-to-Use Endoscope Channels Hiding?: Unraveling the Risks of Safe Reuse

Contamination due to failures or omissions in the reprocessing steps of gastrointestinal endoscopes is common in clinical practice. Ensuring the proper execution of each step is a challenge for reprocessing personnel. This cross-sectional study was conducted in an endoscopy setting between March and May 2021. We performed interviews about reprocessing practices, analyzed the life history of the equipment, and performed inspections through a borescope video of gastrointestinal endoscope channels that were stored and ready for use. A borescope is a complementary tool used to validate endoscope reprocessing, evaluate the internal visualization of channels, and identify changes that can compromise the safety of its use, which are often not detected in the leak test. Thirteen biopsy channels from stored gastrointestinal endoscopes were inspected. We found that 85% had stains and grooves, 69% contained moisture, and 46% had debris. There was at least one noncompliance issue in all of the channels inspected.

Efficacy of high-level disinfection of endoscopes contaminated with Streptococcus equi subspecies equi with 2 different disinfectants

BACKGROUND

Prevention of spread of Streptococcus equi subspecies equi (S. equi) after an outbreak is best accomplished by endoscopic lavage of the guttural pouch, with samples tested by culture and real time, quantitative polymerase chain reaction (qPCR). Disinfection of endoscopes must eliminate bacteria and DNA to avoid false diagnosis of carrier horses of S. equi.

HYPOTHESIS/OBJECTIVES

Compare failure rates of disinfection of endoscopes contaminated with S. equi using 2 disinfectants (accelerated hydrogen peroxide [AHP] or ortho-phthalaldehyde [OPA]). The null hypothesis was that there would be no difference between the AHP and OPA products (based on culture and qPCR results) after disinfection.

METHODS

Endoscopes contaminated with S. equi were disinfected using AHP, OPA or water (control). Samples were collected before and after disinfection and submitted for detection of S. equi by culture and qPCR. Using a multivariable logistic regression model-adjusted probability, with endoscope and day as controlled variables, the probability of an endoscope being qPCR-positive was determined.

RESULTS

After disinfection, all endoscopes were culture-negative (0%). However, the raw unadjusted qPCR data were positive for 33% AHP, 73% OPA, and 71% control samples. The model-adjusted probability of being qPCR-positive after AHP disinfection was lower (0.31; 95% confidence interval [CI], -0.03-0.64) compared to OPA (0.81; 95% CI, 0.55-1.06), and control (0.72; 95% CI, 0.41-1.04).

CONCLUSION AND CLINICAL IMPORTANCE

Disinfection using the AHP product resulted in significantly lower probability of endoscopes being qPCR-positive compared to the OPA product and control.

Mechanical deformation of elastomer medical devices can enable microbial surface colonization

Elastomers such as silicone are common in medical devices (catheters, prosthetic implants, endoscopes), but they remain prone to microbial colonization and biofilm infections. For the first time, our work shows that rates of microbial surface attachment to polydimethylsiloxane (PDMS) silicone can be significantly affected by mechanical deformation. For a section of bent commercial catheter tubing, bacteria (P. aeruginosa) show a strong preference for the 'convex' side compared to the 'concave' side, by a factor of 4.2. Further testing of cast PDMS materials in bending only showed a significant difference for samples that were manually wiped (damaged) beforehand (1.75 × 10⁴ and 6.02 × 10³ cells/mm² on the convex and concave sides, respectively). We demonstrate that surface microcracks in elastomers are opened under tensile stress (convex bending) to become 'activated' as sites for microbial colonization. This work demonstrates that the high elastic limit of elastomers enables these microcracks to reversibly open and close, as 'dynamic defects'. Commercial catheters have relatively high surface roughness inherent to manufacturing, but we show that even manual wiping of newly-cast PDMS is sufficient to generate surface microcracks. We consider the implication for medical devices that feature sustained, surgical, or cyclic deformation, in which localized tensile conditions may expose these surface defects to opportunistic microbes. As a result, our work showcases serious potential problems in the widespread usage and development of elastomers in medical devices.

Criteria for the Use, Processing, and Disposal of Flexible Endoscope Cleaning Brushes

Objectives: To ensure effectiveness in the endoscope channel cleaning process, using functional brushes that are in good condition is necessary. This study sought to identify the criteria for acquiring, using, and disposing of cleaning brushes at endoscopy facilities in Brazil. We further sought to evaluate the conditions of the cleaning brushes in use in the facilities. Methods: This cross-sectional study was conducted between July 2021 and January 2022. Personnel responsible for processing endoscopes were interviewed regarding the use, processing, and disposal of flexible endoscope cleaning brushes. In addition, the brushes used to clean the equipment were inspected. Results: All participants interviewed reported the practice of brushing endoscope channels. Of them, 60% noted the use of disposable brushes, with 40% using reusable brushes. None of the facilities interviewed reported discarding disposable brushes after use. The protocols for disposal of brushes included disposing due to bristle wear (70%), disposal at the end of the day (20%), and an absence of disposal protocols (10%). In addition, 30% of facilities did not clean the bristles before reintroducing them into the channel/lumen, and no facility had an established routine for cleaning brushes between uses. Inspection of brushes revealed that only 20% of facilities had new brushes with no signs of wear or damage. Conclusion: The use of inappropriate brushes/sponges for cleaning endoscope channels and the lack of criteria for the reuse and disposal of brushes increases the risk of cross-contamination, internal damage to channels, and biofilm formation.

Bacterial exposure risk to the endoscopist's face while performing endoscopy

Objectives

Gastrointestinal endoscopy increases the risk of bacterial exposure to endoscopists. However, before 2019, most endoscopists did not pay attention to microorganism transmission from patients. This study aimed to investigate the incidence of bacterial exposure to endoscopists' faces during gastrointestinal endoscopic procedures using the bacterial culture method.

Methods

This was a single-centered, retrospective study including endoscopists who performed various gastrointestinal endoscopy procedures at the Division of Endoscopy, Hirosaki University Hospital between August 31 and October 6, 2020. Endoscopists wore surgical masks and affixed pre-sterilized films over them. Following the gastrointestinal endoscopic procedures, attached microbes were collected from the endoscopists' surface films using sterilized swabs. Collected microorganisms were cultured on tryptic soy agar and 5% sheep blood agar, and the incidence of bacterial exposure was determined by bacterial culture positivity. Cultured bacteria were identified by gram staining and 16S rRNA gene sequencing.

Results

Bacterial culture positivity was 12.6%, and it was significantly higher in therapeutic than in diagnostic endoscopy. Notably, therapeutic endoscopy increased bacterial culture positivity in colonoscopy, but not in esophagogastroduodenoscopy. Staphylococci, including Staphylococcus epidermidis and Staphylococcus capitis, were the most commonly found bacteria in samples identified through 16S rRNA gene sequencing.

Conclusions

The risk of bacterial exposure to the endoscopist's face was increased in colonoscopy treatment procedures. Therefore, endoscopists should be aware of the significant risk of microbial infection from scattering fluid that comes from the endoscopy's working channel.

Guidelines for Robotic Flexible Endoscopy at the Time of COVID-19

Flexible endoscopy involves the insertion of a long narrow flexible tube into the body for diagnostic and therapeutic procedures. In the gastrointestinal (GI) tract, flexible endoscopy plays a major role in cancer screening, surveillance, and treatment programs. As a result of gas insufflation during the procedure, both upper and lower GI endoscopy procedures have been classified as aerosol generating by the guidelines issued by the respective societies during the COVID-19 pandemic-although no quantifiable data on aerosol generation currently exists. Due to the risk of COVID-19 transmission to healthcare workers, most societies halted non-emergency and diagnostic procedures during the lockdown. The long-term implications of stoppage in cancer diagnoses and treatment is predicted to lead to a large increase in preventable deaths. Robotics may play a major role in this field by allowing healthcare operators to control the flexible endoscope from a safe distance and pave a path for protecting healthcare workers through minimizing the risk of virus transmission without reducing diagnostic and therapeutic capacities. This review focuses on the needs and challenges associated with the design of robotic flexible endoscopes for use during a pandemic. The authors propose that a few minor changes to existing platforms or considerations for platforms in development could lead to significant benefits for use during infection control scenarios.

Persistence of Legionella in Routinely Disinfected Heater-Cooler Units and Heater Units assessed by Propidium Monoazide qPCR

BACKGROUND

Evidence to date indicates that heater-cooler units (HCUs) and heater units (HUs) can generate potentially infectious aerosols containing a range of opportunistic pathogens such as Mycobacterium chimaera, other non-tuberculous mycobacterial (NTM) species, Pseudomonas aeruginosa and Legionella spp. Our purpose was to determine the extent of Legionella contamination and total viable count (TVC) in HCUs and HUs and to analyze the relationship by water system design of devices of two different brands (LivaNova vs. Maquet).

METHODS

Legionella spp. were detected and quantified by our optimized PMA-qPCR protocol; TVCs were assessed according to ISO protocol 6222. Analyses were performed in the first sampling round and after six months of surveillance.

RESULTS

Overall, Legionella spp. was detected in 65.7% of devices. In the second sampling round, Legionella positivity rates were significantly lower in water samples from the Maquet devices compared to the LivaNova ones (27.3% vs. 61.5%). LivaNova HCUs also yielded more Legionella, and aquatic bacteria counts than Maquet in both first and second-round samples.

CONCLUSIONS

We recommend that all surgical patients and staff exposed to aerosols from thermoregulatory devices should be followed up for Legionella infection and that microbiological surveillance on such devices should be conducted regularly as precautionary principle.