September 07, 2016
2 min read

Scope contamination occurs despite reprocessing guideline compliance

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Persistent bacterial growth, sometimes of high-concern pathogens, can occur on duodenoscopes and linear echoendoscopes despite reprocessing and high-level disinfection techniques as recommended by practice guidelines and scope manufacturers, recent study data confirmed.

“Our findings confirm the potential for transmission of bacteria between patients despite seemingly appropriate and optimal reprocessing techniques, as noted in the concluding remarks of panel members at the May 14 to 15, 2015 FDA advisory panel meeting,” Jack J. Brandabur, MD, from Swedish Gastroenterology in Seattle, and colleagues wrote.

Jack J. Brandabur, MD

Jack J. Brandabur

In light of the recent high-profile outbreaks of multidrug resistant organisms associated with endoscopic retrograde cholangiopancreatography (ERCP) scopes, Brandabur and colleagues evaluated the cleaning and reprocessing practices used within 21 Providence Health & Service and affiliate facilities, which collectively perform more than 4,500 ERCP procedures annually.

For at least 30 days at each facility, they collected daily surveillance cultures from 106 duodenoscopes and linear echoendoscopes after they were reprocessed and dried. They also sought to determine whether the scope manufacturer, age, and automatic endoscope reprocessing (AER) system had any effect on the culture-positivity rate.

Overall, 5% of 4,032 total culture specimens and 8.4% of 2,238 total encounters were positive for microbial growth after recommended bedside and manual cleaning, AER and drying. Moreover, 0.6% of specimens and 0.9% of encounters were contaminated with high-concern pathogens, but none were multidrug resistant organisms. These pathogenic organisms were cultured from 14 of the scopes evaluated. Two scopes from different facilities had multiple repeat positive results and were returned to their manufacturers.

“The elevator mechanism was implicated in all our positive high-concern culturing encounters with clearly reported culture site,” Brandabur and colleagues wrote. “This lends evidence that the elevator, with its complex and difficult to clean design, might be the culprit underlying recent outbreaks.”

Culture-positivity rates varied widely across facilities and different cleaning and culturing processes, but did not vary significantly based on scope model, manufacturer, age, the type of manual or bedside cleanser used or the automatic flushing system used. However, there were significantly fewer high-concern pathogens detected when Custom Ultrasonics AERs — which have since been recalled by the FDA — were used compared with Medivators AERs.

“Significantly greater high-concern pathogen recovery from nonultrasonic AERs suggests that further investigation should be undertaken to confirm our results,” the researchers wrote.

They concluded that the variability in culture-positivity rates across facilities “highlights the importance of multicenter studies in examining the multistep, operator-dependent, complex cleaning and reprocessing of” duodenoscopes and linear echoendoscopes, and added that they are planning a prospective study “with standardized culture methods to determine whether an already available, enhanced reprocessing method such as double [high level disinfection] will enhance the margin of safety for ... patients.” – by Adam Leitenberger

Disclosures: The researchers report no relevant financial disclosures.