Use of ethylene-oxide gas sterilisation to terminate multidrug-resistant bacterial outbreaks linked to duodenoscopes

Abstract

BackgroundCleaning and high-level disinfection have been the standard in the USA and other countries for reprocessing flexible endoscopes, including duodenoscopes and other types of gastrointestinal endoscopes. For decades, this practice has been a cornerstone for infection prevention in the endoscopic setting. However, amid recent reports associating the use of duodenoscopes with infections and outbreaks of carbapenem-resistant Enterobacteriaceae (CRE) and related multidrug-resistant organisms (MDROs), reasonable questions about the adequacy of current practices for reprocessing duodenoscopes have emerged.ObjectivesTo review and evaluate the adequacy of current reprocessing practices for preventing duodenoscopes from transmitting CRE and related MDROs.MethodsThe MEDLINE/PubMed database was searched to identify published cases associating confirmed (or suspected) infections of CRE or a related MDRO with exposure to a duodenoscope since 2012, when duodenoscopes became a recognised risk factor for the transmission of CRE. The Internet was also searched to identify news articles and other reports documenting eligible cases occurring during this same timeframe but not identified during the MEDLINE database’s search. The Food and Drug Administration’s (FDA) medical device database was queried to identify regulatory reports describing these same types of cases, also recorded since 2012. The clinical and reprocessing details of each eligible case were reviewed to identify (when possible): (a) the reprocessing method (e.g., high-level disinfection) performed at the time of the infections, (b) whether the facility’s compliance with the manufacturer’s reprocessing instructions was confirmed, and (c) the measure(s) or corrective action(s) the facility implemented to prevent additional multidrug-resistant infections.ResultsSeventeen cases in the USA and six in other countries (primarily Europe) associating infections (and colonizations) of CRE or a related MDRO with exposure to a duodenoscope were reviewed. Fourteen of these 23 outbreaks were caused by CRE, and six by a related MDRO. Two of these six latter cases identified Klebsiella pneumoniae carrying the mcr-1 gene as the pathogen. For 12 of these 23 cases, it was reported or implied that the duodenoscope was being high-level disinfected at the time of the infections, consistent with published guidelines. For the remaining 11 cases, the associated report(s) did not clearly identify how the duodenoscope was being reprocessed at the time of the infections (although it may be reasonably concluded that at least some, if not all, of these 11 cases involved high-level disinfection).Further, eight of the 23 cases reported the duodenoscope was being reprocessed in accordance with the manufacturer’s instructions for use (and professional guidelines) at the time of the infections. Seven of the cases discussed the design of the duodenoscope (eg, the forceps elevator mechanism) in the context of reprocessing and the infections. Three of the cases identified one or more reprocessing lapses, including inadequate cleaning, delayed reprocessing and improper drying and/or storage of the duodenoscope. Most of these 23 cases were associated with exposure to a duodenoscope model featuring a sealed elevator-wire channel. Six of the cases reported adopting (or in one case supplementing high-level disinfection with) ethylene oxide (EO) gas sterilisation of the duodenoscope, with at least three reporting this measure terminated the outbreak. Other measures adopted to prevent additional infections included removing the implicated duodenoscope from use, re-training staff about proper cleaning, microbiological culturing of the duodenoscope and returning the duodenoscope to the manufacturer for evaluation, maintenance and/or repair.ConclusionsThis study's findings suggest current reprocessing practices may not always be sufficiently effective to prevent a duodenoscope from transmitting CRE and related MDROs, at least in some circumstances including an outbreak setting. Factors this review identifed that may contribute to the device remaining contaminated after reprocessing include the device’s design; breaches of recommended reprocessing guidelines (eg, inadequate manual cleaning, delayed reprocessing or improper device storage); damage to the device; lacking servicing, maintenance or repair; and/or the presence of biofilms. Measures that can mitigate the impact of these and other reprocessing challenges and reduce, if not eliminate, the risk of transmission of CRE or a related MDRO by a duodenoscope include the use of EO gas sterilization (or another comparably effective process or method). In 2015, the FDA suggested healthcare facilities consider performing at least one of four supplemental measures, which include EO gas sterilisation, to improve the effectiveness of duodenoscope reprocessing. Whether the FDA and Centers for Disease Control and Prevention might reclassify duodenoscopes as critical devices requiring sterilisation is currently unresolved.

Multisociety guideline on reprocessing flexible GI endoscopes and accessories

“…Factors such as endoscope design, lapses in reprocessing guidelines, damage to the endoscope, or a lack of servicing, maintenance, and repair of the endoscope were hypothesized to be contributors to these outbreaks. 53 In this review, 6 of 17 studies implemented EtO sterilization as an intervention during infectious outbreaks; in at least 3 and possibly 6 studies this intervention yielded an absence of culture positivity from duodenoscopes at all sites, thereby stopping the outbreaks. 6,7,[54][55][56][57] Similar data exist for EtO sterilization ceasing outbreaks attributed to bronchoscopes.…”

“…EtO sterilization of duodenoscopes can be an effective tool in some clinical situations, specifically when there are infectious outbreaks observed among patients who have undergone ERCP. A systematic review by Muscarella 53 examined all reported carbapenem-resistant Enterobacteriaceae-and multidrug-resistant organisms-related infections in the United States and Europe attributed to duodenoscope exposure and assessed the adequacy of reprocessing in these outbreaks. Factors such as endoscope design, lapses in reprocessing guidelines, damage to the endoscope, or a lack of servicing, maintenance, and repair of the endoscope were hypothesized to be contributors to these outbreaks.…”

Remote video auditing in the endoscopy unit for evaluation of duodenoscope reprocessing in a tertiary care center

“…Bartles et al hypothesized that a second round of high-level disinfection may reduce culture positivity; ultimately, however, no difference was found between single and double high-level disinfection [36]. As a result, some studies have suggested switching to sterilization procedures in order to decrease rates of contamination [37]; however, limitations to this process exist as well [38].…”

Recent Advances in Endoscope Disinfection: Where Do We Stand in the COVID era?

“…( 38 ) A review of cases worldwide reported that 6 of 23 Carbapenem-Resistant Enterobacteriaceae or MDRO-related outbreaks were treated by adding EtO sterilization; this measure successfully terminated 3 of those 6 outbreaks. ( 39 ) However, there are multiple barriers to widespread use of EtO including cost, potential toxicity to reprocessing staff, and possible damage to endoscopes.…”