Detection of bacteria in dialysate and its antibody in long-term hemodialysis patients.

The relationship between endotoxin, which was detected in the dialysate, and incidence of its antibody formation in long-term hemodialysis patients was studied. Bacteria in the dialysate were first obtained, identified, and cultured, and then endotoxin was obtained from the bacteria by extraction with phenol. Using the endotoxin obtained and Escherichia coli J-5 as the antigen, the endotoxin antibody was measured in the serum of long-term hemodialysis patients by enzyme-linked immunosorbant assay (ELISA). It was found that the percentage of endotoxin antibody-positive patients was significantly higher in hemodialysis patients when compared with healthy controls. It was also significantly higher in hemodialysis patients using synthetic polymer membrane dialyzers compared with those using cuprophan membrane dialyzers. These results suggest that endotoxin antibody detected in hemodialysis patients was derived from the dialysate, and that the dialysate must be kept bacteria free, especially in patients using high-flux, highly permeable membrane dialyzers.