By Andrew S. Ross, MD

Section Head, Gastroenterology Virginia Mason Medical Center, Seattle, WA, USA

Over the past 40 years, the practice of endoscopic retrograde cholangiopancreatography (ERCP) has revolutionized the management of pancreaticobiliary disorders. What once required an invasive, open surgical procedure has been transformed into an endoscopic procedure which can often be performed on an outpatient basis.  Key to this transformation has been the development of the duodenoscope and its associated elevator mechanism. While the elevator mechanism facilitates many of the therapeutic interventions performed during ERCP, it greatly increased the complexity of the design- which has subsequent implications for the cleaning of the instrument.

Beginning in 2012, reports began to emerge in the medical literature describing outbreaks of multidrug resistant bacterial infections in patients who had undergone ERCP. Subsequent reports followed throughout the world, all of which failed to identify an associated breach in the high-level disinfection (HLD) process. In several of the reported outbreaks, the culprit bacteria were cultured from within the elevator mechanism, even after the scope had undergone several rounds of HLD. In fact, one report demonstrated a 1.9% rate of HLD failure after sequential culture of over 1,500 duodenoscopes. Based on these data and other observations, it has become clear that in clinical practice, the HLD process for duodenoscopes does not reliably result in an instrument which is free of potential pathogens.

The revelation that the duodenoscope could be a vector for the transmission of bacteria between patients has polarized the endoscopy community throughout the world. ERCP is an important procedure for patients with very few or no minimally invasive therapeutic alternatives. On the other hand, most endoscopists and patients agree that the transmission of bacterial pathogens between patients by a medical instrument is unacceptable. Solutions have been slow to materialize. While HLD protocols have been validated in a laboratory setting, they have never been fully validated in clinical practice. The United States Food and Drug Administration (FDA) has now mandated post-market surveillance for duodenoscope HLD protocols from each of the three duodenoscope manufacturers. The Olympus Corporation has implemented a new, FDA-approved cleaning brush, as well as a scheduled routine maintenance program and a voluntary recall for the 180-series duodenoscope to allow for retrofitting of the elevator mechanism.  Finally, the FDA has suggested enhanced methods for duodenoscope reprocessing to be implemented, to include routine culturing, gas sterilization with ethylene oxide, liquid chemical sterilization or repeat HLD.

Infection as a potential ERCP-related adverse event was always thought to be related to instrumentation of the obstructed pancreaticobiliary tree. The emergence of multidrug resistant bacterial organisms and the use of pulsed-gel electrophoresis have resulted in “fingerprinting” of the bacteria in each of the reported outbreaks. This has allowed, in many cases, for tracing of the culprit bacteria back to the use of a duodenoscope. The story which has played out in the mass media related to each of these outbreaks has focused on the transmission of highly resistant organisms between patients via the duodenoscope. A pan-sensitive organism transmitted by the duodenoscope is unlikely to be recognized, flagged, “fingerprinted” and traced back to the duodenoscope, yet it still represents a significant threat to patient safety as it relates to ERCP. The real story focuses on the transmission of any organism between patients by the duodenoscope.

The infection issue related to the duodenoscope is a problem not only in centers where outbreaks have been well described, but wherever ERCP is practiced. Endoscopists must focus on appropriate indications for ERCP and provide exhaustive informed consent- including a discussion of the potential for bacterial cross-contamination. Each endoscopy unit where ERCP is performed should understand mechanisms for detecting potential infections and undertake enhanced methods for reprocessing duodenoscopes. The landscape surrounding the performance of ERCP has changed; our primary focus should be on enhancing the safety of this procedure on behalf of the patients we serve.

General references:

  1. Ross AS, Baliga C, Verma P, Duchin J, Gluck M. A quarantine process for the resolution of duodenoscope-associated transmission of multidrug-resistant Escherichia coli. Gastrointest Endosc  2015 82(3):477-83
  2. Supplemental Measures to Enhance Duodenoscope Reprocessing [http://www.fda.gov/medicaldevices/safety/alertsandnotices/ucm454766.htm].