Relative Frequency of Microorganisms in Piped Water and Dialysis Fluid in the Hemodialysis Section of Alzahra Hospital, Iran

Background: Patients under hemodialysis are exposed to remarkable volume of water. As dialysis water is in direct contact with patients’ blood, absence of regular disinfection of pipes will facilitate the transfer of the endotoxins produced by bacteria in water to the patient's body. Thus, regular control of dialysis system and water disinfectant equipment is compulsory. This study aimed at comparing relative frequency of positive culture for microorganisms in piped water before and after filtration, culture of water after passing from pipes, and culture of dialysis fluid before entering the dialysis filter in hemodialysis section of Alzahra Medical Center (Isfahan, Iran). Methods: During 2010 and 2012, an interventional study was performed in Alzahra Hospital. Samples were taken from piped water before and after filtration and from dialysis fluid before passing from membrane. The obtained samples were cultured in tryptic soy agar (TSA) and the isolated bacteria were then evaluated. Interventions included the disinfection of pipes used for transmission of water and replacement of pipes in hemodialysis section. Findings: Purified water was studied before and after passing the pipes. Dialysis fluid was also assessed before and after the intervention. Bacteria had grown in eight out of 14 samples (57%) before the intervention. In fact, five samples developed Escherichia coli, three had pseudomonas, and one had candida. However, after the intervention, only one out of 14 samples was found to have bacteria (alcaligenes) after filtration and before entering dialysis water pipes. Conclusion: According to the results of this study, the probability of bacterial growth is very high in filtration system of dialysis water. Regular disinfection and microbial sampling and culture are hence crucial. Keywords: Hemodialysis, Dialysis fluid, Microbial contamination