Bacterial contamination of heat-sterilized, heat-disinfected and chemically-disinfected haemodialysis monitors.

The bacterial contamination of one heat-sterilized, three heat-disinfected and four chemically-disinfected monitor types was evaluated before and after dialysis. All monitor types were contaminated. In the heat-treated monitors the level of contamination varied with the intensity of the heat treatment and the technical design. They were less contaminated than the chemically-disinfected recirculating single-pass monitors. The latter were contaminated to a marginal degree, irrespective of the quality of the water supply. Each monitor showed a characteristic microbial flora, indicating that recontamination occurred from the same persistent focus. Aquired antibiotic resistance characters were rare among the potential human pathogens isolated from the dialysate. The level of contamination during dialysis is determined by a complex of factors, including the mode of disinfection, the technical design of the dialysis equipment, the duration of the dialyses, and the flora of the dialysate.