Optimizing endoscope surveillance: how sampling methods and time points affect microbiological surveillance

Endoscope-associated infections remain a persistent concern despite adherence to reprocessing guidelines. Microbial surveillance is essential for quality control, but its effectiveness may depend on sampling timing and technique.

This prospective multi-centre study was conducted across three gastrointestinal endoscopy units within multiple campuses of a tertiary general hospital in Wuhan, China. Sampling was performed either immediately after high-level disinfection (HLD) or following overnight storage in a dry cabinet using one of two techniques: the conventional flushing sampling method (CFSM) or the flush-brush-flush sampling method (FBFSM).

The overall pass rate for disinfected digestive endoscopes was 83.4% (212/254). Compared with CFSM, FBFSM exhibited a significantly lower overall pass rate (χ²=5.895, P=0.015), indicating enhanced microbial recovery. Endoscopes sampled after overnight drying showed a significantly higher pass rate (87.7% vs 79.3%) and lower detection rates for high-concern organisms, particularly Pseudomonas spp. and Gram-positive cocci, compared with samples collected immediately after HLD.

The drying phase of endoscope reprocessing plays a critical role in reducing residual microbial contamination. Additionally, FBFSM demonstrated superior sensitivity in post-reprocessing surveillance, highlighting its value as a more effective sampling method compared with CFSM.