Microbiological quality of hemodialysis water in a three-year multicenter study in Uruguay

The microbiological quality of treated water is a very important issue in hemodialysis (HD) centers. Water treatment may have a dramatic effect on microbial contamination because of bacterial colonisation of the different parts of the system such as storage tanks, softeners or deionisers. Therefore, HD centers must have stringent quality programmes including regular water monitoring for microbiological analysis. We report the results of a three-year study (July 97 to June 2000) including bacteriological quality analysis of 3129 water samples from 32 out of 38 HD centers throughout Uruguay.

Bacteriological analysis of water samples was based on heterotrophic count, total coliform count and Pseudomonas aeruginosa presence/absence, according to the procedures proposed by the Association for the Advancement of Medical Instrumentation (AAMI).

Heterotrophic counts of 83% of the samples were under 200 colony forming units (CFU) /mL (AAMI limit of compliance) and the water samples after the final bactericidal treatment showed 99% compliance. The points showing the worst results were softeners and deionisers (60% acceptance).

In comparison with a similar study in Uruguay, from January 96 to June 97 at the same microbiological laboratory, there has been a marked improvement in the microbiological quality of water for hemodialysis.