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

Abstract

Background. Despite endoscope reprocessing, residual droplets remain in gastrointestinal endoscope working channels. Inadequate drying of gastrointestinal endoscope working channels may promote microbial reproduction and biofilm formation, increasing the risk of infection in patients. This review was designed to provide the current status of gastrointestinal endoscope drying, emphasize the importance of gastrointestinal endoscope drying, and evaluate the effectiveness of different drying methods of gastrointestinal endoscope in reducing residual droplets and microbial growth risk. Methods. A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting checklist. The PubMed, Web of Science, Medline, EMBASE, EBSCO, CNKI, CQVIP, and Wanfang Data databases were searched from 2010 to 2020 to identify eligible articles focused on methods of gastrointestinal endoscope drying and the status of endoscope drying. The following key points were analyzed: type of intervention, amount of residual droplets, major microbial types, and effectiveness of biofilm intervention. JBI quality assessment tool was used to determine bias risk for inclusion in the article. Results. This review included twelve articles. Two of the articles reported lack of drying of gastrointestinal endoscopes while the other ten reported residual droplets, microbial growth, and biofilm formation after different methods of drying. Four articles reported 0 to 4.55 residual droplets; four articles reported that the main microbial types were cocci and bacilli, most commonly Staphylococcus, Escherichia coli, Bacillus maltophilia, and Pseudomonas aeruginosa; and two reported that drying could effectively reduce biofilm regeneration. The type of intervention is as follows: automatic endoscopy reprocessor (AER), manual compressed air drying, and the Dri-Scope Aid for automatic drying and drying cabinet. Conclusions. While endoscope reprocessing may not always be effective, an automatic endoscope reprocessor plus the Dri-Scope Aid with automatic drying over 10 min or storage in a drying cabinet for 72 h may be preferred.

Effectiveness of adenosine triphosphate to monitor manual cleaning and disinfection efficacy of flexible endoscopes in Hong Kong

“…Temperature and humidity are two environmental factors for bacterial growth on flexible endoscopes. 10 In the Endoscopy and Day Surgery Center, we have installed temperature and humidity meters at the storage room for continuous monitoring and recording of storage condition according to the Society of Gastroenterology Nurses and Associates (SGNA) Standard (Temperature 20–22°C; Humidity <75%). 5 In this study, we have obtained “Pass” on ATP surveillance (<200 RLU) and no bacterial growth on culture on all flexible endoscopes after HLD by AER and at 4 h or 24 h of storage from endoscopy surfaces and channel rinsate samples.…”

“…In Union Hospital, Hong Kong, 15 128 endoscopic procedures were performed in 2021, highlighting the vital importance of endoscope reprocessing in our busy endoscopy unit. 10 In 2019 and 2020, 4.47% and 5.38% of microbiological tests were found to be culture‐positive in Union Hospital as compared with 12–24% in Western reports, respectively. 11 A series of improvement plans were made to address the issue of bacterial contamination of reprocessed endoscopes, including (i) improving the reprocessing cleanliness level of biopsy channel valves; (ii) changing gloves when handling the flexible endoscopes after manual cleaning to prevent cross contamination; (iii) competency training and audit of reprocessing staff on manual cleaning of endoscopes; (iv) competency training on culture sampling and ATP measurement of flexible endoscopes was initiated; and (v) environmental enhancement with continuous monitoring of temperature and relative humidity in the endoscope storeroom.…”

“…In Union Hospital, Hong Kong, 15 128 endoscopic procedures were performed in 2021, highlighting the vital importance of endoscope reprocessing in our busy endoscopy unit 10 . In 2019 and 2020, 4.47% and 5.38% of microbiological tests were found to be culture‐positive in Union Hospital as compared with 12–24% in Western reports, respectively 11 .…”

Storage of gastrointestinal endoscopes: when is the safe time for re-use?

“…In this context, Pseudomonas aeruginosa stands out, a gram-negative pathogen with positive tropism for humid environments, such as a water reservoir and flexible endoscope channels. It is also characterized by its ease in forming biofilms; it has structures that are difficult to remove and have great potential for transmission, especially in immunocompromised patients, as they are at greater risk of developing infections (38)(39)(40) .…”

Performance comparison of reusable versus disposable colonoscopes:a non-inferiority Trial

“…There are typically eight reprocessing steps before reuse of a colonoscopy endoscope: precleaning, leak testing, manual cleaning, rinsing after cleaning, visual inspection for contamination, high-level disinfection, rinsing after high-level disinfection, and drying [13]. However, even after reprocessing and drying, gastrointestinal endoscopes were found to still have microbial growth, residual droplets, and biofilm formation [14], and therefore, completely preventing infections after endoscopy seems impossible despite the medical practices being guided by such rigorous guidelines [5, 15, 16]. Therefore, the patient-to-patient infection transmission risk should be eliminated by the design of disposable colonoscopes [17].…”