Comparative evaluation of filters for sustained bacterial control in endoscope reprocessing final rinse water.

BACKGROUND

Filter performance is critical for maintaining endoscope final rinse water quality, however comparative data on different filter types remain limited.

METHODS

Brominated polystyrene hydantoin (BPSH), polyethersulfone (PES), polypropylene (PP) filters were challenged with water containing ∼10⁶ CFU/mL Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. Performance was assessed under dynamic (3.6 L/min flow, 6h/day) and static (8-day stagnation) conditions.

RESULTS

Under dynamic conditions, the BPSH filter consistently maintained effluent bacterial concentrations ≤10 CFU/100 mL for all three organisms throughout the 64-day study. In contrast, the PES and PP filters showed progressive deterioration in performance. Under static conditions, BPSH maintained <1 CFU/100 mL for all organisms over 7 days, whereas PES and PP exceeded the limit from day 2 for P aeruginosa and E coli, and from day 6 for S aureus.

DISCUSSION: The sustained efficacy of BPSH under both dynamic and static conditions is attributed to the continuous release of active bromine. This release kills retained bacteria and offers a significant advantage over conventional physical filters.

CONCLUSION

BPSH provides consistent, high bacterial removal under both conditions, ideal for clinical settings with intermittent downtime.