A study of the bacterial flora contaminating haemodialysis fluids.

The microbiological flora of waters and dialysates used in human haemodialysis, were investigated by qualitative and quantitative methods over a five year period. The work was based on samples taken in the Brighton Renal Dialysis Unit, where only one type of haemodialysis machine, the Travenol R. S. P. , was in use; for the purpose of comparison, samples were obtained from twenty-eight other dialysis centres using a variety of haemodialysis machines. The species contaminating fluids were identified, and their source, and factors responsible for their persistence and proliferation, were investigated. Quantitative studies of contamination were related to the machine design, and to working practices in the unit. The quality of mains waters, and treated waters produced by water purification plants used in haemodialysis, were investigated by microscopic and cultural methods. The endotoxin levels of waters, dialysates, and bacterial cultures, were investigated by the Limulus method which was modified in order to reduce the cost of quantitative studies. The clinical relevance of microbiological data obtained in the study, was assessed by studies of patients case notes and temperature recordings. The fluids and equipment used by several patients suffering from pyrexial episodes during haemodialysis, were investigated by cultural methods and endotoxin assay; serological studies of these patients were also carried out