Comparison of Sampling Methods for Detecting Protein in Gastrointestinal Endoscopes

Area of Science:

• Medical Microbiology
• Biomedical Engineering
• Infection Control

Background:

• Persistent microbial contamination on flexible endoscopes is a significant cause of patient infections and outbreaks.
• Effective cleaning of endoscopes is crucial for high-level disinfection and sterilization success.
• Existing sampling methods often fail to detect residual protein and bioburden, necessitating improved techniques.

Purpose of the Study:

• To compare the effectiveness of turbulent fluid flow (TFF) sampling with flush-only sampling for protein detection in manually cleaned gastrointestinal endoscopes.
• To assess the ability of TFF sampling to identify residual contamination missed by conventional methods.

Main Methods:

• A crossover study design was employed, comparing TFF and flush-only sampling on the same endoscopes after manual cleaning.
• Protein levels were quantified using spectrophotometry after collecting samples with sterile water via both methods.
• Forty encounters with 20 unique gastrointestinal endoscopes (colonoscopes and gastroscopes) were analyzed.

Main Results:

• Turbulent fluid flow (TFF) sampling detected residual protein in 22.5% of endoscopes (9/40 samples), with levels ranging from 1-4 μg/mL.
• Flush-only sampling detected zero protein in all samples.
• Four samples with detectable protein exceeded the 2 μg/mL threshold for recleaning; three of these were reduced to ≤2 μg/mL after recleaning.

Conclusions:

• Turbulent fluid flow (TFF) sampling is more effective than flush-only sampling in detecting residual protein in manually cleaned gastrointestinal endoscopes.
• The findings underscore the need for more robust sampling methods to ensure effective endoscope reprocessing and patient safety.
• Further research is warranted to establish the real-world utility of TFF systems for verifying bioburden removal.