Hemodialysis Water Research Articles

Less water for haemodialysis: is multiple pass the future pace to go?

Less water for haemodialysis: is multiple pass the future pace to go?

Less water for haemodialysis: is multiple pass the future pace to go?

Less water for haemodialysis: is multiple pass the future pace to go?

Dialysis Water Treatment Systems: From past to Present

In the past dialysis was associated with typical syndromes, such as “hard water syndrome”, aluminium-linked encephalopathy and osteomalacia, and pyrogenic reactions. With time it was recognized that water required treatment before being used for haemodialysis. With experience, the type of water for haemodialysis changed from tap to decalcified, then to demineralised, next to osmosis and finally ultra-pure water, the current gold standard. At present, water treatment systems involve pre-treatment, real treatment and a hydraulic circuit. The pre-treatment process removes suspended particles which would damage the osmotic membranes. Real treatment prepares water for haemodialysis by using reverse osmosis. The hydraulic circuit distributes osmotic water to the dialysis room and into each machine. The water treatment systems considered were supplied by Fresenius, Gambro and Farmacastelli. They differ from one another in treatment protocols, construction and disinfection systems.

Quality of hemodialysis water in a resource‐poor country: The Nigerian example

Hemodialysis (HD) patients are exposed to large volumes of water, separated from patients' blood by semipermeable membrane of dialyzers. Chemical contaminants in poorly treated water impact negatively on quality of life of these patients. This survey was carried out to assess the HD water quality in Lagos, Nigeria. Ten milliliters of feed and treated water from all six HD centers in Lagos were tested for aluminum, copper, zinc, magnesium, calcium using atomic absorption spectrometry; sodium and potassium were tested using flame photometry, fluoride with molecular photoluminescence method; sulfate using turbidimetry, nitrates measured by cadmium column reduction method, chloramines and free chlorine were measured using N, N-diethyl-1-P-phenylenediamine colorimetric method. Information on sources of feed water, frequency of testing of HD water, methods of water treatment, type of water purification system and maintenance was also obtained. All centers used borehole as main source of water supply. None of the centers met Association for the Advancement of Medical Instrumentation (AAMI) guidelines for most chemical contaminants. Only chlorine (0.48 ± 0.07 mg/L) and potassium (3.9 ± 0.95 mg/L) levels met AAMI standards after treatment. Mean levels of chemical contaminants in treated water were as follows: aluminum 0.04 ± 0.01 mg/L, zinc 0.27 ± 0.08 mg/L, chloramines 0.16 ± 0.03 mg/L, fluoride 1.83 ± 0.40 mg/L, sulfate 117 ± 86.1 mg/L which were mildly elevated; calcium 126.00 ± 22.7 mg/L, sodium 179 ± 25.6 mg/L, and nitrate 70.5 ± 50.8 mg/L, which were markedly elevated; and magnesium 8.3 ± 3.38 mg/L, which was moderately elevated above AAMI recommended levels. HD water quality is poor in our environment. Concerted efforts are required to ensure good quality water for HD.

Hospital Water Supply as a Potential Source of Opportunistic Pathogens

In Egypt as well as in many other developing count ries, there are no specific standards for hospital water. Even water is free from the traditi onal bacterial indicators, it may represent a sourc e of health hazards especially for elderly, children and patients under dialysis due to the presence of opportunistic pathogenic bacteria. The study was ca rried out on the bacteriological water quality at the intakes as well as the end of water treatment t rain of two water treatment plants that supplying three hospitals located in Greater Cairo, Egypt wit h water that used for different purposes. Samples of the raw water supply for the two water treatment plants (Nile River water) showed ranges of 10 2 - 10 5 cfu mL -1 , 10 2 -10 4 MPN 100 mL -1 , 10 2 -10 4 MPN 100 mL -1 and 10 2 -10 3 MPN 100 mL -1 for Heterotrophic Plate Count (HPC) bacteria, Total Col iforms (TC), Fecal Coliforms (FC) and Fecal Streptococci (FS), respectively. Treated water show ed considerable reduction in HPC while the other bacterial indicators reached the undetectable level. The distribution system impact on treated water quality was limited to causing an increase in HPC bacteria. A study was carried out to determine the presence of Pseudomonas aeuginosa , Aeromonas spp. and Staphylococcus aureus in hospitals tap water, water reservoirs, as well as w ater for preparation of hemodialysis fluids. Although the post-chlorinated water in both water t reatment plants was free from bacterial indicators, it still contaminated with the three st udied opportunistic pathogenic bacteria. The detected opportunistic pathogens may be attributed to the distribution system condition and/or the presence of storage tanks. Hemodialysis water sampl es showed the higher percentage of P. aeruginosa isolates which represent a major source of health r isk to patient's attending dialysis process in hospitals and clinics. The presence of o pportunistic bacteria in drinking water and dialysate with absence of coliform and low HPC suggested that the criteria for drinking water are usually not adequate for water used in hospitals. T he purpose for which the water is to be used determines the criteria for water quality. Storage of water should be as hygienic as possible.

Microbiological evaluation of the efficiency of hot RO water only used to disinfect hemodialysis water distribution loop in operation for 5 years

Microbiological evaluation of the efficiency of hot RO water only used to disinfect hemodialysis water distribution loop in operation for 5 years

Electrochemical Impedance Spectroscopy as a tool for materials selection: Water for haemodialysis

The water used in haemodialysis must meet very stringent purity criteria to avoid infections. Mineral salts are removed through inverse osmosis and/or ion exchange membranes down to produce very low conductivity values (<1 μ S cm −1 typically), and organic contaminants are removed through adsorption by activated carbon filters. The insidious development of biofilms at stagnant areas such as pipe joints and wall roughness requires periodic disinfection of pumps and piping circuitry. Because disinfectants are highly oxidant chemicals, they tend to induce localised corrosion in the metallic parts of the system, which in turn creates new potential sites for biofilm development. Thus, the optimal combination of disinfectant and material that is acceptable, limiting biofilm development, must be determined. The following two stainless steels were studied: medical grade austenitic AISI 316L, commonly used, and a duplex austenitic–ferritic SAF 2205, which is a possible replacement material. The following two disinfectants were also employed: sodium hypochlorite and peracetic acid. Both disinfectants were used at dosages in the range typically used in the medical industry. The results show that the SAF 2205 and peracetic acid are the best combination of material and disinfectant because they produce the fastest repassivation kinetics and the smoothest surfaces during the disinfection treatment of all combinations studied. The results are interpreted in terms of morphology and kinetics of development of the passive film.

Removal of Viable Bacteria and Endotoxins by Electro Deionization (EDI)

Viable bacteria and endotoxins in water sometimes cause problems for human health. Endotoxins are major components of the outer cell wall of gram-negative bacteria (lipopolysaccharides). In medical procedures, especially haemodialysis (HD) and related therapies (haemodiafiltration (HDF), haemofiltration (HF)), endotoxins in the water for haemodialysis can permeate through the haemodialysis membrane and cause microinflammation or various haemodialysis-related illnesses. To decrease such a biological risk, RO and UF membranes are generally used. Also, hot water disinfection or the chemical disinfection is regularly executed to kill bacteria which produce endotoxins. However, simple treatment methods and equipment may be able to decrease the biological risk more efficiently. In our experiments, we confirmed that viable bacteria and endotoxins were removed by Electro Deionization (EDI) technology and also clarified the desorption mechanisms.

Cantel Medical's Mar Cor Purification subsidiary acquires Gambro's US water business

Through its Mar Cor Purification subsidiary, Cantel Medical Corp has continued the expansion of its water purification and filtration segment by acquiring the exclusive rights in the USA to manufacture and sell Gambro's water treatment products used in the production of water for haemodialysis.

Haemodialysis water production by double reverse osmosis

A filtration unit composed of two reverse osmosis membranes in series was evaluated for haemodialysis water production. For this purpose, hard and soft water were formulated based on European drinking water directives. The study showed that the double reverse osmosis process is efficient to produce haemodialysis water with the quality defined by the pharmacopeia requirements from synthetic soft water and hard water. In both cases, nitrate and sodium ions diffuse through the membrane limiting the water treatment. This phenomenon is correlated to the electrostatic interactions, the Donnan effect and the ion diffusivity, which govern the membrane selectivity.

The level of endotoxins in hemodialysis water and dialysate in Lithuanian hemodialysis centers

The composition and quality of the dialysis fluid play an important role in the modulation of dialysis-related complications. During hemodialysis, patient's blood has a contact with dialysate through a semipermeable membrane. Bacterial endotoxins can pass through the membrane pores into the patient's blood and cause a silent chronic microinflammation. The aim of this study was to determine the level of endotoxins in hemodialysis water and dialysate in Lithuanian hemodialysis centers. Dialysis water (n=50) and dialysate (n=50) were collected from 91% (n=50) of all hemodialysis centers. The presence of bacterial endotoxins was evaluated using a sensitive Limulus amebocyte lysate test, which detects intact lipopolysaccharides. The level of endotoxins was lower than 0.25 EU/mL in 43 (86%) dialysis water samples and in 46 (92%) dialysate samples, and complied with the recommendations of the European Pharmacopoeia and the European Best Practice Guidelines for pure dialysis fluid. The dialysate of 39 (78%) Lithuanian hemodialysis centers complied with the definition of an ultrapure dialysis fluid. The water and dialysate were of insufficient quality in 14% and in 8% of Lithuanian hemodialysis centers, respectively, and this could be improved by the establishment of routine investigation of endotoxins.

Electronic tongue for simultaneous detection of endotoxins and other contaminants of microbiological origin

Endotoxins, also referred to as pyrogens, are lipopolysaccharides (LPS) present in the outer membrane of Gram-negative bacteria, and represent one of the most dangerous microbiological contaminants in water for hemodialysis and intravenous infusion. A method is presented for the simultaneous detection of endotoxins and other bacterial lysis contaminating species in purified water for parenteral formulations. The technique used is electrochemical impedance spectroscopy, with data interpretation using principal component analysis (PCA), cluster analysis (CA), and multivariate discriminant analysis (MDA). Two types of electrode surfaces were modified with LPS recognition agents: (i) a 37 amino acids fragment of a 18 kDa cationic antimicrobial protein (CAP18F) that has LPS binding activity; (ii) the highly selective endotoxin neutralizing protein (ENP). Statistical multivariate analysis of the impedance spectral data allowed the detection of endotoxin at, and below, the threshold pharmaceutical regulatory level. Discrimination of LPS from samples containing proteins, nucleic acids, phospholipids or their mixtures was achieved. These results open a new route to a practical instrumental method capable of detecting and discriminating LPS from other potential pro-inflammatory species of microbiological origin, such as nucleic acids.

Mycobacterium llatzerense sp. nov., a facultatively autotrophic, hydrogen-oxidizing bacterium isolated from haemodialysis water

Six mycobacterial isolates from haemodialysis water, conforming a homogeneous phylogenetic group in a previous multigenic analysis, were classified taxonomically. Physiological and biochemical characterization, as well as DNA-DNA hybridizations, demonstrated that the isolates were facultatively autotrophic, aerobic and hydrogen-oxidizing bacteria, representing a novel species in the rapid growing Mycobacterium group, for which the name Mycobacterium llatzerense sp. nov. is proposed. The type strain is MG13(T) (=CECT 7273(T)=CCUG 54744(T)).

Occurrence of fungi in water used at a haemodialysis centre

The aim of this study was to identify and determine the diversity, occurrence and distribution of fungi in water used at a haemodialysis centre. Samples in the hydraulic circuit for the distribution of the water, dialysate samples and samples of sterilization solution from dialysers were collected over a 3-month period, and 500 ml of each sample was filtered through membranes. All together 116 isolates of fungi were recovered from 89% of all water samples collected inside the haemodialysis unit, with prevalence of moulds in tap water samples and of yeasts in dialysate samples. Fusarium spp. was the most abundant genus found, whereas Candida parapsilosis was the predominant yeast species. This study demonstrated that various fungi were present in the water system. These data suggest the inclusion of the detection and quantification of fungi in the water of haemodialysis. The recovery of fungi from aqueous haemodialysis environments implies a potential risk for haemodialysis patients and indicates the need for continuous maintenance and monitoring. Further studies on fungi in haemodialysis water systems are required to investigate the organism ability to persist, their role in biofilm formation and their clinical significance.

Determinação simultânea de As, Cd e Pb em amostras de água purificada para hemodiálise por espectrometria de absorção atômica com forno de grafite, após otimização multivariada baseada no uso de planejamento experimental

This paper reports the development of a methodology for simultaneously determining As, Cd and Pb, employing GF AAS with polarized Zeeman-effect background correction. In order to make the procedure applicable, the influence of pyrolysis and atomization temperatures and the amount of chemical modifiers were studied. Factorial and central composite designs were used to optimize these variables. Precision and accuracy of the method were investigated using Natural Water Reference material, Nist SRM 1640. Results are in agreement with certified values at the 95% confidence limit when the Student t-test is used. This methodology was used for quality control of purified water for hemodialysis.

Description of Pelomonas aquatica sp. nov. and Pelomonas puraquae sp. nov., isolated from industrial and haemodialysis water

Description of Pelomonas aquatica sp. nov. and Pelomonas puraquae sp. nov., isolated from industrial and haemodialysis water

Description of Pelomonas aquatica sp. nov. and Pelomonas puraquae sp. nov., isolated from industrial and haemodialysis water

Three Gram-negative, rod-shaped, non-spore-forming bacteria (strains CCUG 52769T, CCUG 52770 and CCUG 52771) isolated from haemodialysis water were characterized taxonomically, together with five strains isolated from industrial waters (CCUG 52428, CCUG 52507, CCUG 52575T, CCUG 52590 and CCUG 52631). Phylogenetic analysis based on 16S rRNA gene sequences indicated that these isolates belonged to the class Betaproteobacteria and were related to the genus Pelomonas, with 16S rRNA gene sequence similarities higher than 99% with the only species of the genus, Pelomonas saccharophila and to Pseudomonas sp. DSM 2583. The type strains of Mitsuaria chitosanitabida and Roseateles depolymerans were their closest neighbours (97.9 and 97.3% 16S rRNA gene sequence similarity, respectively). Phylogenetic analysis was also performed for the internally transcribed spacer region and for three genes [hoxG (hydrogenase), cbbL/cbbM (Rubisco) and nifH (nitrogenase)] relevant for the metabolism of the genus Pelomonas. DNA-DNA hybridization, major fatty acid composition and phenotypical analyses were carried out, which included the type strain of Pelomonas saccharophila obtained from different culture collections (ATCC 15946T, CCUG 32988T, DSM 654T, IAM 14368T and LMG 2256T), as well as M. chitosanitabida IAM 14711T and R. depolymerans CCUG 52219T. Results of DNA-DNA hybridization, physiological and biochemical tests supported the conclusion that strains CCUG 52769, CCUG 52770 and CCUG 52771 represent a homogeneous phylogenetic and genomic group, including strain DSM 2583, clearly differentiated from the industrial water isolates and from the Pelomonas saccharophila type strain. On the basis of phenotypic and genotypic characteristics, these strains belong to two novel species within the genus Pelomonas, for which the names Pelomonas puraquae sp. nov. and Pelomonas aquatica sp. nov. are proposed. The type strains of Pelomonas puraquae sp. nov. and Pelomonas aquatica sp. nov. are CCUG 52769T (=CECT 7234T) and CCUG 52575T (=CECT 7233T), respectively.

Diversity of Environmental Mycobacterium Isolates from Hemodialysis Water as Shown by a Multigene Sequencing Approach

Here we used a multigene sequencing approach for the identification and molecular typing of environmental mycobacteria of the fast-growing subgroup. Strains were isolated from hemodialysis water and clinical samples. Eleven type strains of related species of the genus were also included in this study. To gain further insight into the diversity of the environmental mycobacteria, we analyzed several housekeeping genes (16S rRNA, ITS1, gyrB, hsp65, recA, rpoB, and sodA). No individual phylogenetic tree allowed good discrimination of all of the species studied. However, a concatenated and a consensus analysis, combining the genes, allowed better discrimination of each strain to the species level, and the increase in sequence size also led to greater tree robustness. This approach is useful not only for the discrimination and identification of environmental mycobacteria but also for their molecular typing and studies of population genetics. Our results demonstrate high genetic diversity among the isolates obtained, which are probably new species of the genus.

A molecular microbial ecology approach to studying hemodialysis water and fluid

Bacteria, or bacteria-derived products, might be responsible for deleterious effects in hemodialysis patients. Most microorganisms in hemodialysis water, including potential pathogens, are difficult to isolate and might subsist in a 'viable but not culturable' state or may need specific culture media. A molecular culture-independent approach based on the analysis of the 16S rDNA obtained from total DNA has been used to better know the diversity of bacteria inhabiting hemodialysis water and fluid, and to address the possible health effects associated with their presence. Four clone libraries from 16S rDNA (274 clones) were analyzed to characterize the species or groups of bacteria present, to assess their distribution in the water circuit, and to compare the results with those previously obtained in culture-dependent analysis. One hundred and ninety-seven clones of four gene libraries were analyzed by sequencing, and were identified phylogenetically. Clones affiliated to the Alphaproteobacteria group led the diversity. The presence in several samples of Alpha-4-proteobacteria, recognized as sphingolipids producers, was to be noted. The most abundant clones were affiliated to the Betaproteobacteria branch, closely related to the genus Herbaspirillum. As known, Alphaproteobacteria and Betaproteobacteria genomes might present a manifest excess in CpG sequences and most of them show a lipopolysaccharide-rich outer membrane, both described as inducers of innate immunity responses. Another abundant group, belonging to the Cyanobacteria class, a possible source of cyanotoxins, was not related to any previously cultured bacterium. Possible risk implications for hemodialysis patients of the bacterial community detected are discussed.

Determination of Aluminum Traces in Hemodialysis and Tap Water Using Standard Method's Procedure Modified and Flow Injection Ionic Exchange Preconcentration

A procedure for the spectrophotometric determination of aluminum traces in water using a flow injection (FI) preconcentration system has been proposed. The flow system was made up of a peristaltic pump, an injector‐commutator, and a minicolumn filled with 300.0 mg of Amberlite IR‐120 cationic exchange resin. After the preconcentration step, aluminum was eluted by a 4.0 mol l−1 HCl solution. In a second stage, out of the flow system, the eluate was neutralized with a 4.0 mol l−1 NaOH solution. The aluminum was submitted to the reaction with eriochrome cyanine to form a chelate in solution buffered to pH 5.85, according to the Standard Method's procedure with some modifications, and this was followed by spectrophotometric detection. Chemical and flow variables were studied in the preconcentration system. The precision of the proposed method was calculated for a solution containing 46.8 µg l−1 of Al(III), when 40.0 ml of solution were preconcentrated (n=7), and their respective relative standard deviation (RSD) was 1.8%. The detection limit obtained was 1.7 µg l−1 of Al(III) (sample volume=40.0 ml). The proposed method was successful in determining aluminum in water certified reference material.