Bacteriological contamination of dialyzers. Clinical, bacteriological and scanning electron-microscopic evaluation of different dialysate mixing systems.

Membranes from Gambro Lundia Nova dialyzers were investigated for presence of bacteria after hemodialysis with centrally and peripherally mixed dialysate. Centrally mixed dialysate was found contaminated with Pseudomonas aeruginosa, and bacterial cultures as well as electron scanning micrographs showed the presence of these bacteria on the dialysate side as well as on the blood side of membranes from dialyzers perfused with this dialysate during hemodialysis. No bacteria were found on membranes used with peripherally mixed dialysate, in which very few bacteria were found. Despite this the frequency of febrile episodes in patients submitted to hemodialysis with the two different dialysate mixing systems showed no significant difference in our material.