Comparison on the efficacy of disinfectants used in automated endoscope reprocessors: PHMB-DBAC versus orthophthalaldehyde

Background/Aims: Since endoscopes are reusable apparatus classified as semicritical item, thorough reprocessing to achieve high-level disinfection is of utmost importance to prevent spread of infection. To improve disinfection efficacy and safety, disinfectants and endoscope reprocessors are continuously evolving. This study aimed to compare the efficacy of the combination of polyhexamethylenebiguanide hydrochloride-alkyldimethylbenzylammonium chloride (PHMB-DBAC) and orthophthalaldehyde (OPA) used respectively in ultrasonographic cleaning incorporated automated endoscope reprocessors: COOLENDO (APEX Korea) or OER-A (Olympus Optical). Methods: A total of 86 flexible upper endoscopes were randomly reprocessed with either COOLENDO/PHMB-DBAC or OER-A/OPA. Culture samplings were done at two sites (endoscope tip and working channel) which were later incubated on blood agar plate. Bacterial colonies were counted and identified. Results: The culture-positive rate at the endoscope tip and working channel was 0% and 2.33% for COOLENDO/PHMB-DBAC and 4.65% and 0% for OER-A/OPA. Staphylococcus hominis was cultured from one endoscope reprocessed with COOLENDO/PHMB-DBAC and Pseudomonas putida was isolated from two endoscopes reprocessed with OER-A/OPA. Conclusions: The reprocessing efficacy of COOLENDO/PHMB-DBAC was non-inferior to that of OER-A/OPA (p=0.032; confidence interval, -0.042 to 0.042). During the study period, significant side effect of PHMB-DBAC was not observed.