AIM:To conduct a bacterial culture study for monitoring decontamination of automated endoscope reprocessors(AERs) after high-level disinfection(HLD).METHODS:From February 2006 to January 2011,authors conducted randomized consecutive sampling each month for 7 AERs.Authors collected a total of 420 swab cultures,including 300 cultures from 5 gastroscope AERs,and 120 cultures from 2 colonoscope AERs.Swab cultures were obtained from the residual water from the AERs after a full reprocessing cycle.Samples were cultured to test for aerobic bacteria,anaerobic bacteria,and mycobacterium tuberculosis.RESULTS:The positive culture rate of the AERs was 2.0%(6/300) for gastroscope AERs and 0.8%(1/120) for colonoscope AERs.All the positive cultures,including 6 from gastroscope and 1 from colonoscope AERs,showed monofloral colonization.Of the gastroscopeAER samples,50%(3/6) were colonized by aerobic bacterial and 50%(3/6) by fungal contaminations.CONCLUSION:A full reprocessing cycle of an AER with HLD is adequate for disinfection of the machine.Swab culture is a useful method for monitoring AER decontamination after each reprocessing cycle.Fungal contamination of AERs after reprocessing should also be kept in mind. AIM: To conduct a bacterial culture study for monitoring decontamination of automated endoscope reprocessors (AERs) after high-level disinfection (HLD). METHODS: From February 2006 to January 2011, authors conducted randomized consecutive sampling each month for 7 AERs.Authors collected a total of 420 swab cultures, including 300 cultures from 5 gastroscope AERs, and 120 cultures from 2 colonoscope AERs. Swab cultures were obtained from the residual water from the AERs after a full reprocessing cycle. Samples were cultured to test for aerobic bacteria, anaerobic bacteria , and mycobacterium tuberculosis .RESULTS: The positive culture rate of the AERs was 2.0% (6/300) for gastroscope AERs and 0.8% (1/120) for colonoscope AERs.All the positive cultures, including 6 from gastroscope and 1 from colonoscope AERs, showed monofloral colonization. Of the gastroscope AER samples, 50% (3/6) were colonized by aerobic bacterial and 50% (3/6) by fungal contaminations. CONCLUSION: A full reprocessing cycle of an AER with HLD is adequate for disinfection of the machine. Swab culture is a useful method for monitoring AER decontamination after each reprocessing cycle. Fungal contamination of AERs after reprocessing should also be kept in mind.