Persistent contamination of a duodenoscope working channel in a non-clinical simulated ERCP setting

Abstract

Background To mitigate duodenoscope contamination, recent design enhancements have primarily focused on the distal tip. However, the working channels remain unchanged, which may be linked to biofilm formation. We assessed the persistence of microorganisms, indicative of biofilm formation, in reprocessed duodenoscopes in a non-clinical endoscopic retrograde cholangiopancreatography (ERCP) simulation setting.

Methods Three new duodenoscopes were over-soiled in non-clinical ERCP simulations followed by reprocessing. After 40 tests, the Pseudomonas aeruginosa strain in the soil (Pa-type 1) was switched to a different P. aeruginosa strain (Pa-type 2) for 20 subsequent tests. Cultures of the tip and working channel were acquired after high level disinfection and overnight storage.

Results One duodenoscope showed persistent growth of P. aeruginosa from the fifth test until the end of the study. Pa-type 1 remained present until the end of the study in the cultures of this duodenoscope, even after discontinuation of exposure to that specific strain. The other two duodenoscopes only showed incidental contamination.

Conclusion Persistent contamination by Pa-type 1 was seen in one out of three duodenoscopes after exposure to supraphysiological levels of gut microorganisms. No clear explanation was found for this persistent contamination as exposure and handling were identical and no abnormalities of this particular duodenoscope were identified by borescope inspection.

^* contributed equally to this work

Publication History

Received: 27 July 2021

Accepted after revision: 28 February 2022

Article published online:
05 May 2022

• References

• 1 Olsen I. Biofilm-specific antibiotic tolerance and resistance. Eur J Clin Microbiol Infect Dis 2015; 34: 877-886
• 2 Kovaleva J, Peters FT, van der Mei HC. et al. Transmission of infection by flexible gastrointestinal endoscopy and bronchoscopy. Clin Microbiol Rev 2013; 26: 231-254
• 3 Alfa MJ, Ribeiro MM, da Costa Luciano C. et al. A novel polytetrafluoroethylene-channel model, which simulates low levels of culturable bacteria in buildup biofilm after repeated endoscope reprocessing. Gastrointest Endosc 2017; 86: 442-451 e441
• 4 Pajkos A, Vickery K, Cossart Y. Is biofilm accumulation on endoscope tubing a contributor to the failure of cleaning and decontamination?. J Hosp Infect 2004; 58: 224-229
• 5 Alfa MJ, Olson N. Physical and composition characteristics of clinical secretions compared with test soils used for validation of flexible endoscope cleaning. J Hosp Infect 2016; 93: 83-88
• 6 Alfa MJ, Degagne P, Olson N. Worst-case soiling levels for patient-used flexible endoscopes before and after cleaning. Am J Infect Control 1999; 27: 392-401
• 7 Advisory Board Cleaning and Disinfection Flexible Endoscopes (SFERD). Professional standard handbook, version 5.0. Flexible endoscope cleaning and disinfection. Available from (Accessed: 23 March 2022): https://www.vdsmh.nl/publicaties/flexibele-endoscopen/sferd-handboek-versie-50-2019
• 8 Centers for Disease Control and Prevention. Duodenoscope Surveillance Sampling and Culturing Protocols. Available from: Accessed: 25 March 2022 https://www.fda.gov/media/111081/download
• 9 Dutch Association for Medical Microbiology. [Guideline control of microbiological safety of thermolabile flexible high-risk gastrointestinal endoscopes.]. Available from: Accessed: 23 March 2022 https://www.nvmm.nl/media/2222/180627-richtlijn-controle-op-microbiologische-veiligheid-van-thermolabiele-flexibele-gi-endoscopen-juiste-versie.pdf
• 10 U.S. Food and Drug Administration. The FDA is recommending transition to duodenoscopes with innovative designs to enhance safety: FDA Safety Communication. Available from: Accessed: 23 March 2022 https://www.fda.gov/medical-devices/safety-communications/fda-recommending-transition-duodenoscopes-innovative-designs-enhance-safety-fda-safety-communication
• 11 Johani K, Hu H, Santos L. et al. Determination of bacterial species present in biofilm contaminating the channels of clinical endoscopes. Infect Dis Health 2018; 23: 189-196
• 12 Kovaleva J, Meessen NE, Peters FT. et al. Is bacteriologic surveillance in endoscope reprocessing stringent enough?. Endoscopy 2009; 41: 913-916