Double Reprocessing Decontaminates Duodenoscopes

Caroline Helwick

May 26, 2016

SAN DIEGO — A double-reprocessing protocol can help reduce the rate of duodenoscope-associated infection, new research shows.

"Traditionally, most centers use single high-level disinfection. We've been using double reprocessing, and it has definitely decreased the positive culture rate of the duodenoscopes," said Ji Young Bang, MD, a third-year fellow in gastroenterology at Indiana University in Indianapolis.

"To keep all our patients safe, we aspire to a 0% culture rate. Although we didn't get the positive culture rate down to zero, we haven't had any duodenoscope-associated infections since we started doing this," she told Medscape Medical News.

Carbapenem-resistant Enterobacteriaceae (CRE) infection is a challenge to treat because these organisms are resistant to extended-spectrum beta-lactamase antibiotics. Mortality rates from CRE can reach 50%, Dr Bang and her team report.

Since 2013, several CRE outbreaks in the United States have been associated with endoscopic retrograde cholangiopancreatography (ERCP), despite institution-specific high-level disinfection protocols. Because of the elevator mechanism on duodenoscopes, it is difficult to completely remove organic material during manual cleaning, Dr Bang explained.

After two cases of ERCP-associated CRE at the Indiana University Medical Center, a novel high-level double-reprocessing duodenoscope disinfection protocol was implemented.

The impact of this protocol on ERCP-associated CRE transmissions was presented here at the Digestive Disease Week (DDW) 2016.

Double-Reprocessing Protocol

Before any duodenoscope was used, it underwent two cycles of manual cleaning and automated reprocessing, which involved a high-level disinfectant that is 22% hydrogen peroxide, 5% peroxyacetic acid, and 4.3% trisodium phosphate.

Each week during the 9-month study period, Dr Bang's team cultured 10 to 20 duodenoscopes that had undergone double-reprocessing disinfection. Altogether, 28.4% of the scopes they used were tested. For the first 3 months, both the working channels and the elevators were cultured, but because all the channels tested negative, only the elevators were cultured after that.

Duodenoscopes that had negative cultures were released for use. Those with positive cultures were cleaned, processed, and cultured again. If they were still positive, they underwent ethylene oxide gas sterilization; if they were negative, they were released for use.

Double Reprocessing Halves the Rate of Pathogen Positivity

Of the 610 duodenoscopes cultured during the study period, 59 (9.7%) were positive. However, only five (0.8%) of these were positive for potentially pathogenic organisms — a very low rate, Dr Bang reported.

"None of the cultures were positive for CRE, and no ERCP-associated infections have been identified since the implementation of this high-level disinfection protocol," she said.

In a report on the single reprocessing of 1524 duodenoscopes from the Virginia Mason Medical Center in Seattle, the overall culture positivity rate was 13.1% and the pathogenic culture positivity rate was 1.9% (Gastrointest Endosc. 2015;82:477-483). Two of these organisms were multidrug-resistant Escherichia coli.

The double reprocessing of duodenoscopes appears to be more effective in the prevention of duodenoscope-associated transmission of CRE, and results from targeted periodic culturing likely reflect the low risk of using pathogen-contaminated duodenoscopes, Dr Bang said.

"Additional modifications are currently being made to improve this high-level disinfection process to further minimize duodenoscope culture-positive rates," she added.

"We are considering culturing all our duodenoscopes, which is one method of ensuring safety. We will probably also try an alternative liquid chemical sterilant," she told Medscape Medical News. "We know that further improvements are required to achieve complete eradication of microorganisms from duodenoscope cultures."

"We are not at 0%" when it comes to disinfecting duodenoscopes, said John Vargo, MD, from the Cleveland Clinic's Digestive Disease and Surgery Institute.

"We are not yet perfectly reprocessing these instruments, but it's a solution in evolution," he said, predicting that better cleaning approaches and better scope designs will make a difference.

The most essential element remains the physical cleaning of the scopes, he emphasized. Each center is striving for quality reprocessing and surveillance.

Most duodenoscope-related infections are related to human error, said Grace Elta, MD, medical director of the medical procedures unit at the University of Michigan in Ann Arbor, who is chair of the DDW council.

"We still have humans cleaning the scopes," she pointed out. "Most units are now doing their best to eliminate the human error factor."

"There is a call to arms for endoscopists to ensure that their own reprocessing policies are in line," Dr Vargo added.

Dr Bang, Dr Vargo, and Dr Elta have disclosed no relevant financial relationships.

Digestive Disease Week (DDW) 2016: Abstract 719. Presented May 23, 2016.

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