title: Efficacy of Biofilm Removal From Hemodialysis Piping.
abstract: BACKGROUND
  Central dialysate fluid delivery systems (CDDS) are used by dialysis centers in Japan, and although these systems are effective 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 efficacy of these agents at the electron microscope level.
  
  
  OBJECTIVE
  In this study, we used electron microscopy to evaluate the effectiveness 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 disinfectants 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 effective at biofilm removal when heated than at room temperature. Peracetic acid was highly effective at biofilm removal at both room temperature and when heated.
  
  
  CONCLUSIONS
  Cleaning and disinfection using a disinfectant at a high temperature and high concentration effectively removes biofilms from hemodialysis piping. However, long-term exposure to disinfectants may affect the piping material.
authors.affiliation: Department of Medical Engineering, School of Health Science, Kyusyu University of Health and Welfare, Miyazaki, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Isakozawa
authors.affiliation: Department of Medical Engineering, School of Health Science, Kyusyu University of Health and Welfare, Miyazaki, Japan.
authors.forename: Heihachi
authors.initials: H
authors.lastname: Migita
authors.affiliation: Department of Medical Engineering, School of Health Science, Kyusyu University of Health and Welfare, Miyazaki, Japan.
authors.forename: Shingo
authors.initials: S
authors.lastname: Takesawa
keywords: Biofilm; Central Dialysate Fluid Delivery System; Dialysate Line Management; Water Quality Management