Decoupling contamination from infection: Seven years of postendoscopic bloodstream infections and device-patient correlation in an academic medical center, Singapore.

BACKGROUND

Endoscope-associated infections (EAIs) are an underrecognized subset of healthcare-associated infections. Despite advances in reprocessing, routine microbiological surveillance continues to detect residual contamination, but its clinical significance outside outbreak settings remains unclear.

METHODS

We conducted a retrospective surveillance study at a 1,900-bed academic medical center from January 2018 to December 2024. Patients undergoing endoscopic procedures were monitored for bloodstream infections (BSIs) within 30 days. Endoscope microbiological surveillance followed Gastroenterological Society of Australia guidelines. Bloodstream isolates were compared with surveillance culture organisms, and device-level trace-back assessed epidemiological linkage.

RESULTS

Among 316,533 procedures, 2,366 post-endoscopic BSIs occurred (7.5 per 1,000 procedures). Rates were highest after bronchoscopy (47.7 per 1,000) and endoscopic retrograde cholangiopancreatography (36.0 per 1,000), with lower rates after gastroscopy, cystoscopy, and colonoscopy. No epidemiological or microbiological linkage was identified between contaminated endoscopes and post-procedural BSIs.

CONCLUSIONS

Post-endoscopic BSIs occurred at 7.5 per 1,000 procedures, with higher rates after bronchoscopy and ERCP likely reflecting procedural invasiveness and host susceptibility. No epidemiological signal suggested exogenous transmission from contaminated endoscopes, supporting a low likelihood of such transmission. Integrating microbiological surveillance with EHR-based outcome monitoring provides a scalable framework for endoscope safety assurance.