Contamination of single-use biopsy forceps: a prospective in vitro analysis

Abstract

Background: It has been suggested that single-use biopsy forceps prevent interpatient transmission of infection during endoscopy. Passage of sterile forceps through the accessory channel of the endoscope may lead to contamination, however, if the endoscope has been inadequately processed. The potential for contamination of single-use biopsy forceps at various stages of endoscope reprocessing was prospectively evaluated.

Methods: A total of 50 disposable biopsy forceps were passed through the accessory channels of 10 colonoscopes at the following stages of reprocessing: (1) before use in patients to establish a baseline of high-level disinfection, (2) directly after colonoscopy to confirm contamination with use, (3) after manual cleaning and flushing of the accessory channel to support the claim that manual cleaning significantly decreases bioburden, (4) after manual cleaning and a 2-minute soak in 2% glutaraldehyde to assess for contamination after an inadequate cleaning time, and (5) after manual cleaning and a 20-minute soak in 2% glutaraldehyde. The forceps were then sealed in sterile plastic bags after adding 20 mL of thioglycollate broth medium. The suspension was passed through a 0.2-micron vacuum filter and the filters were cultured. All cultures were incubated more than 48 hours.

Results: Biopsy forceps underwent a total of 50 aerobic and 50 anaerobic cultures. Colony-forming units too numerous to count of GI flora, including Escherichia coli, Klebsiella, Pseudomonas, and Clostridium species, grew on 19 of 20 culture plates from biopsy forceps passed through colonoscopes immediately after use. One plate in this group grew 3 colony-forming units of E coli. Persistence of GI flora was noted on 5 of 20 plates after manual cleaning of the colonoscopes. No GI flora were found on forceps after the colonoscopes after soaking in gluteraldehyde for 2 and 20 minutes. Environmental contaminants including diptheroids, Staphylococcus, and Streptococcus species grew on 16 culture plates.

Conclusions: (1) Single-use biopsy forceps are highly susceptible to contamination during passage through the accessory channels of improperly cleaned endoscopes. (2) Disinfection of the colonoscopes in this study prevented contamination of the forceps at baseline and after reprocessing. (3) Proper endoscope reprocessing may be the most important factor in preventing biopsy forceps-related interpatient infection.