Correlation between the growth of bacterial biofilm in flexible endoscopes and endoscope reprocessing methods

Background: The purpose of this article was to investigate bacterial biofilm formed on endoscopes and to explore the possible correlation between endoscope reprocessing procedures and bacterial biofilm growth on endoscope channels. Methods: Sixty-six endoscope suction and biopsy channels and 13 water and air channels were collected from 66 hospitals throughout China. Scanning electron microscopy was used to observe biofilm growth on the internal surface of these channels. Questionnaires were mailed to 66 endoscopy centers to investigate reprocessing procedures for endoscopes. Results: Obvious biofilm growth was detected on 36 suction and biopsy channels (36/66, 54.6%) and 10 water and air channels (10/13, 76.9%). The percentage of manual cleaning in group B (n ¼ 36, without detection of biofilms) was 92.3% (33/36), whereas it was 50.0% (15/30) in group A (n ¼ 30, with detection of biofilms). Follow-up of group A (n ¼ 30) showed that no biofilm was detected, whereas biofilm was detected in group B. The difference was statistically significant (P ¼ .001). The proportion of detergent reuse in group B was 92.3% (33/36), and it was 61.5% in group A (18/30) (P ¼ .005). The proportion of alcohol-air drying in group B was 38.9% (14/36), and it was 76.7% (23/30) in group A (P ¼ .002). Conclusion: The formation of endoscopic biofilm during clinical practice may be related to reuse of detergent, manual cleaning, and incomplete drying.