Related Experiment Video
Updated: May 31, 2026
Microbial Control and Monitoring Strategies for Cleanroom Environments and Cellular Therapies
Published on: March 17, 2023
Establishing a clinically relevant bioburden benchmark: a quality indicator for adequate reprocessing and storage of
Michelle J Alfa1, Shadi Sepehri, Nancy Olson
1Microbiology Laboratory, St. Boniface General Hospital Research Centre, Winnipeg, Manitoba, Canada. malfa@dsmanitoba.ca
Background:
Microbiological surveillance of patient-ready flexible endoscopes has been suggested as a tool for endoscope reprocessing quality assurance. However, a proper guideline defining the performance and the frequency of monitoring procedures and specifying how to interpret the results is lacking.
Materials And Methods:
All channels from the 20 flexible gastrointestinal endoscopes (5 gastroscopes, 9 colonoscopes, and 6 duodenoscopes) used at an endoscopy clinic were tested for the presence of bacteria and fungi early every Monday morning over a 7-month period.
Results:
Bacteria and fungi were detected in 5.7% of the 383 channels tested. Of the 141 scopes tested, 14.1% had detectable growth in at least 1 channel. No significant relationship was detected between the scope or channel type and detection of microorganisms. Over the 7 months of testing, 99.5% of scope channels consistently demonstrated <100 cfu/mL of microbial growth.
Conclusion:
Based on our clinical findings, we recommend 100 cfu/mL as a reliable and routinely achievable cutoff for bioburden residuals in reprocessed endoscope channels. This cutoff is the same as the Canadian cutoff for dialysis water.
