[Microbiological quality of hemodialysis water: what are the risk factors?]

A dialyzed patient weekly gets in touch with a large amount of water (on average 350 liters) through the dialysis bath. It is therefore essential that this solution would have a high quality and purity. The aim of our study was to monitor the microbiological quality of the hemodialysis water in order to identify possible factors that could affect it.

We conducted a cross-sectional study from January 2015 to October 2017 collecting the dialysis water in AOU Careggi. Samples were aseptically collected by specialized technicians and then transported under ice at 4° C to the Laboratory of Biological Hazards of USL Toscana Centro for laboratory analyses.

126 water samples were collected. Coliforms, E. coli, Staphylococcus aureus, enterococci were not detected. Pseudomonas aeruginosa was found in only one sample. Both for CFU at 37° C and at 22° C, the type of device represented the only statistically significant risk factor (OR 15.21 and OR 10.25 respectively): SDS devices had a significantly higher risk of being positive for CFU at 37° C and 22° C.

As our study demonstrated, the system producing dialysis water must be constantly monitored, especially in cases of SDS devices which may be subjected more frequently to a higher contamination, due to their discontinuous use.