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Risk of contamination of sterile biopsy forceps in disinfected endoscopes
R M Lee1, R A Kozarek, S E Sumida
1Department of Internal Medicine, Virginia Mason Medical Center, Seattle, Washington 98101, USA.
Background:
Previous studies have shown that pathogens may persist within bacterial biofilms in endoscope accessory channels despite high-level disinfection. Breaching the gastrointestinal mucosa with biopsy forceps contaminated at time of passage has the potential to cause cross-infection between patients.
Methods:
We studied contamination risk of sterilized biopsy forceps passed through endoscopes after high-level disinfection. For each trial, five video colonoscopes, duodenoscopes, and gastroscopes were used. All endoscopes had been previously processed and stored for 10 or more hours. Sterile biopsy forceps were inserted and retrieved followed by vortexing the tips in 15 mL of soy broth. Under a laminar flow hood, the broth was filtered through a 0.2 microm millipore membrane and plated. Because of minimal bacterial growth resulting from the above, soy broth (> 20 mL) was flushed through two video colonoscopes, duodenoscopes, and gastroscopes on two occasions and collected. The effluent was plated using a sample of 0.1 mL dilution. The remaining suspension was passed through a millipore filter, and the filter was cultured. All cultures were incubated more than 48 hours.
Results:
Biopsy forceps underwent a total of 24 anaerobic and 75 aerobic cultures. Microbacterial growth occurred on 17 plates: 7 from gastroscopes, 5 from colonoscopes, and 5 from duodenoscopes. Fifteen plates grew staphylococcus for a total of 21 colonies, 1 plate grew 1 colony of propionibacter, 2 plates grew diphtheroids for a total of 4 colonies, and 1 plate grew a single colony of lactobacillus. Cultures from soy broth flushed through the various endoscopes grew on 5 plates: 3 from gastroscopes and 2 from duodenoscopes grew a total of 8 colonies of staphylococcus.
Conclusions:
With proper cleaning technique, a 20-minute soak in 2% glutaraldehyde is effective in disinfecting endoscopes. Although current procedures for endoscope disinfection remain imperfect, we found that in this clinical setting, infection of pathogenic gastrointestinal flora is unlikely when using sterile biopsy forceps.
Insights
Sterile biopsy forceps passed through disinfected endoscopes showed minimal contamination risk, making pathogenic gastrointestinal flora infection unlikely in clinical settings. Proper cleaning techniques are crucial for effective endoscope disinfection.
Area of Science:
- Microbiology
- Infectious Diseases
- Gastroenterology
Background:
- Pathogen persistence in endoscope biofilms despite disinfection poses cross-infection risks.
- Contaminated biopsy forceps can breach the gastrointestinal mucosa, leading to patient-to-patient transmission.
Purpose of the Study:
- To assess the contamination risk of sterilized biopsy forceps used with endoscopes after high-level disinfection.
- To evaluate the potential for cross-infection via contaminated endoscope accessories.
Main Methods:
- Sterilized biopsy forceps were passed through disinfected video colonoscopes, duodenoscopes, and gastroscopes.
- Forceps tips were vortexed in soy broth, filtered, and cultured for microbial growth.
- Soy broth was flushed through endoscopes, and the effluent and filter were cultured.
Main Results:
- Microbial growth occurred on 17 of 99 cultures from biopsy forceps.
- Staphylococcus was the most common contaminant, followed by diphtheroids, propionibacter, and lactobacillus.
- Cultures from flushed soy broth showed Staphylococcus growth on 5 plates.
Conclusions:
- A 20-minute soak in 2% glutaraldehyde is effective for endoscope disinfection with proper cleaning.
- While disinfection procedures are imperfect, pathogenic gastrointestinal flora infection is unlikely with sterile biopsy forceps in this setting.