Elimination of an outbreak of gram-negative bacteremia in a hemodialysis unit

Background: The purpose of this study was to identify the cause of an unusual outbreak of gram-negative bacteremia in patients undergoing long-term hemodialysis. Methods: We performed direct observation and investigation of current dialysis techniques and facilities including microbiological sampling in a long-term hemodialysis unit in a tertiary care center. We also performed a retrospective review of medical charts and laboratory data of 10 patients undergoing long-term hemodialysis who experienced 11 episodes of gram-negative bacteremia between March and June 28, 1993. Results: All of these patients underwent dialysis by jugular venous access. Containers used to collect flush solution after priming of dialysis tubing remained unemptied for extended periods of time, and quantitative culture revealed more than 200 colony-forming units/ml gram-negative bacilli, including species isolated in blood cultures. Dialysis tubing and connector were left submerged in flush solution collection containers during priming, and the process of disinfecting tubing before patient connection had recently been discontinued. Control measures included emptying of flush containers after each use and daily decontamination. All dialysis tubing was to be disinfected before patient connection. Conclusion: Outbreak was due to contamination during dialysis setup. After institution of appropriate control measures, no new cases have occurred