Analysis of positive surveillance cultures of flexible gastrointestinal endoscopes: a 6-year study in a tertiary medical centre in Taiwan.

BACKGROUND/AIM: Proper disinfection of flexible gastrointestinal endoscopes is essential; however, routine surveillance cultures are only recommended in certain countries. This study aimed to evaluate the application of routine surveillance cultures for various endoscope types in a Taiwanese medical centre, and to compare positive culture rates between the different types.

METHODS

A protocol for routine surveillance cultures of endoscopes was implemented at Far Eastern Memorial Hospital (FEMH) from January 2020 to December 2025. Sampling was performed quarterly for standard gastroscopes and colonoscopes, and monthly for duodenoscopes. Beginning in 2024, routine borescope inspection was integrated to assess internal structural damage in endoscopes with persistent contamination.

RESULTS

At the endoscopy centre at FEHM, 532 routine samplings were performed between 2020 and 2025 for gastroscopes and colonoscopes. Gastroscopes exhibited a markedly higher positive rate (6.8%, 19/278) than colonoscopes (0.8%, 2/254) (P < 0.001). Compared with colonoscopes, gastroscopes were associated with significantly higher odds of positive cultures [odds ratio (OR) 7.59, 95% confidence interval (CI) 2.39-38.12; P < 0.001]. Duodenoscopes trended towards higher positivity, but this was not significant (OR 1.70, 95% CI 0.43-9.32; P = 0.462). Enteroscopes had the highest odds of positive cultures among all endoscope types (OR 9.73, 95% CI 2.42-53.88; P = 0.001). For gastroscopes that remained culture-positive despite repeated disinfection, borescope inspection usually demonstrated obvious scratch marks (interior defects) in the working channels, necessitating channel replacement. Pseudomonas aeruginosa was the predominant micro-organism identified, particularly in gastroscopes, likely reflecting scratch marks in the channel.

CONCLUSION

Routine surveillance cultures for endoscopes detects possible disinfection failure.