Efficacy of Biofilm Removal From Hemodialysis Piping

Background: Central dialysate fluid delivery systems (CDDS) are used by dialysis centers in Japan, and although these systems are eective at delivering dialysate, they have a complex piping network with numerous sites where contamination can develop. In Japan, cleaning disinfectants have been clinically evaluated based on endotoxin levels and bacterial counts, but there have been no published studies evaluating the biofilm removal ecacy of these agents at the electron microscope level. Objectives: In this study, we used electron microscopy to evaluate the eectiveness of various cleaning disinfectants in removing biofilms from hemodialysis piping. Methods: Liquid nitrogen was used to sever a section of dialysis piping on which a biofilm had formed during clinical use. Sodium hypochlorite, acetic acid, and peracetic acid were used at stock-solution concentrations as cleaning disinfectants. These disinfec- tants were tested at room temperature and when heated (80°C). After cleaning and disinfection, biofilm removal from the surface of the piping was evaluated using a scanning electron microscope (SEM). Results: Sodium hypochlorite did not show good biofilm removal at room temperature or when heated. Acetic acid was more eective at biofilm removal when heated than at room temperature. Peracetic acid was highly eective at biofilm removal at both room temperature and when heated Conclusions: Cleaning and disinfection using a disinfectant at a high temperature and high concentration eectively removes biofilms from hemodialysis piping. However, long-term exposure to disinfectants may aect the piping material.