Comparison of microbiologic assay methods for hemodialysis fluids (original) (raw)
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Journal of clinical microbiology, 1991
To prevent pyrogenic reactions and bacteremia in hemodialysis patients, the Association for the Advancement of Medical Instrumentation and the Centers for Disease Control recommend culturing of hemodialysis fluids (water and dialysate) at least once a month. The recommendations for total microbial counts are (i) .200 CFU/ml in water used to prepare dialysate or reprocess hemodialyzers and (ii) .2,000 CFU/ml for the dialysate. In accordance with the Association for the Advancement of Medical Instrumentation recommendations all cultures should be incubated at 37°C for 48 h on suitable culture media, such as Trypticase soy agar, standard methods agar, or one of several commercially available assay systems. There have been suggestions that lower temperatures and longer incubation might improve the recovery of bacteria from water and dialysate. In this study bacterial recovery from various dialysis fluids (water, bicarbonate dialysate, and bicarbonate concentrate) at 30 and 37°C was compared. Duplicate sets of samples were membrane filtered (pore size, 0.45 ,um); one set was incubated at 30°C and the other was incubated at 37°C for 72 h. The number of visible colonies was counted every 24 h by using a dissecting microscope. No significant difference was observed in specimens incubated at 37°C for 48 h compared with those incubated at 30°C for 72 h. Also, bacterial recovery was significantly better when samples of bicarbonate dialysate or bicarbonate concentrate were plated on Trypticase soy agar as opposed to standard methods agar.
Bacterial Recovery in Hemodialysis Fluids
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To examine the culture method that could provide the highest bacterial recovery, 150 reverse osmosis water samples used in hemodialysis were collected for comparison of the media (Tryptic Soy Agar, TSA vs Reasoner's 2A Agar, R2A), the ...
Comparison of different culture methods on bacterial recovery in hemodialysis fluids
2004
To examine the culture method that could provide the highest bacterial recovery, 143 reverse osmosis water samples used in hemodialysis were collected for comparison of the media (Tryptic Soy Agar, TSA vs Reasoner's 2A Agar, R2A), the temperature (20 C vs 37 C), the duration of incubation (48-hour vs 7day), and the culture technique (membrane filtration vs spread plate methods). The European Best Practice Guideline method, R2A at 20 C for 7-day incubation provided higher bacterial recovery than the Association for the Advancement of Medical Instrumentation (AAMI) method, TSA at 37 C for 48-hour incubation. The membrane filtration method gave better yield than the spread plate method. As such, the European Best Practice Guideline method in combination with the membrane filtration technique would be the culture method of choice for hemodialysis fluids.
Therapeutic Apheresis and Dialysis, 2009
The Committee of Scientific Academy of the Japanese Society for Dialysis Therapy (JSDT) proposes a new standard on microbiological management of fluids for hemodialysis and related therapies. This standard is within the scope of the International Organization for Standardization (ISO), which is currently under revision. This standard is to be applied to the central dialysis fluid delivery systems (CDDS), which are widely used in Japan. In this standard, microbiological qualities for dialysis water and dialysis fluids are clearly defined by endotoxin level and bacterial count. The qualities of dialysis fluids were classi-fied into three levels: standard, ultrapure, and online prepared substitution fluid. In addition, the therapeutic application of each dialysis fluid is clarified. Since highperformance dialyzers are frequently used in Japan, the standard recommends that ultrapure dialysis fluid be used for all dialysis modalities at all dialysis facilities. It also recommends that the dialysis equipment safety management committee at each facility should validate the microbiological qualities of online prepared substitution fluid. Key Words: Bacteria, Central dialysis fluid delivery system, Endotoxin, Standard of fluid for hemodialysis.
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.
Microbiological contamination of a hemodialysis center water distribution system
Revista do Instituto de Medicina Tropical de São Paulo, 2009
The microbiological monitoring of the water used for hemodialysis is extremely important, especially because of the debilitated immune system of patients suffering from chronic renal insufficiency. To investigate the occurrence and species diversity of bacteria in waters, water samples were collected monthly from a hemodialysis center in upstate São Paulo and tap water samples at the terminal sites of the distribution system was sampled repeatedly (22 times) at each of five points in the distribution system; a further 36 samples were taken from cannulae in 19 hemodialysis machines that were ready for the next patient, four samples from the reuse system and 13 from the water storage system. To identify bacteria, samples were filtered through 0.22 µm-pore membranes; for mycobacteria, 0.45 µm pores were used. Conventional microbiological and molecular methods were used in the analysis. Bacteria were isolated from the distribution system (128 isolates), kidney machine water (43) and reuse system (3). Among these isolates, 32 were Gram-positive rods, 120 Gram-negative rods, 20 Gram-positive cocci and 11 mycobacteria. We propose the continual monitoring of the water supplies in hemodialysis centers and the adoption of effective prophylactic measures that minimize the exposure of these immunodeficient patients to contaminated sources of water.
Physical-chemical and microbiological characterization of water destined to hemodialysis
Revista Ambiente & Água, 2024
This research evaluated the physical-chemical and microbiological parameters of water and dialysate in four distinct hemodialysis units located in the southeast region of Brazil. The physical-chemical parameters evaluated were pH, electric conductivity, turbidity, alkalinity, free chlorine, nitrate, fluoride, chloride, sulfate, sodium, potassium, calcium, and magnesium ion concentrations. Microcystin was also quantified. The microbiological parameters evaluated were the detection of total coliform, total heterotrophic bacteria count (THB), and the isolation and identification of microorganisms in pre-reverse osmosis treatment and post-reverse osmosis treatment water samples and dialysate. The nitrate, fluoride and THB levels found in the water samples may present risk to the patient under hemodialysis treatment. Microcystin was detected in one of the potable water samples. Microorganisms were identified throughout the hemodialysis of the entire water treatment system, with Ralstonia sp. being the most frequent. The presence of emergent pathogenic bacteria highlighted in this study highlights the necessity of microbiological monitoring of water destined for hemodialysis.
Microbiological analysis of hemodialysis water at the Douala General Hospital, Cameroon
International Journal of Science and Research Archive, 2023
Microbiological control of hemodialysis fluid is important for the prevention of hemodialysis-associated illness. Bacterial populations inhabiting a distribution system for hemodialysis water were studied over a 4 month period in five hospitals (one in Tehran, and the others at Alborz). All the samples from the four hospitals at Alborz had colony counts of ≥100 CFU/ ml, which at different points of sampling were higher than the maximum recommended values. A total of 80 samples taken at different points in each hospital's hemodialysis distribution system were collected, and 229 planktonic bacteria isolated on R2A medium. No growth was detected by culturing the samples on Blood agar or Mueller-Hinton agar, according to routine procedures currently used in the five hospitals. A representative of isolates from each of 45 different morphotypes were identified using 16S RNA sequencing. A diverse bacterial community, containing predominantly gram-positive members of Kocuria, Arthrobacter and Staphylococcus and Mycobacterium, was detected. Bacteria from the genera Acinetobacter, Burkholderia, Halomonas, Herbaspirillum, Pseudomonas, and Sphingomonas were identified, which has been described in the build-up of biofilms. Some of the species reported here may represent a health risk to patients receiving hemodialysis treatment. In conclusion, it is recommended that standard protocols for evaluation of microbial contamination be used for regular monitoring and identification of culturable bacteria.
Microbial quality of hemodialysis water, a survey of six centers in Lagos, Nigeria
Hemodialysis International, 2013
Patients with end-stage kidney disease (ESRD) on maintenance hemodialysis (HD) are usually exposed to large volumes of dialysate, which is separated from patients' blood only by thin membrane of dialyzer. It is therefore essential to frequently monitor the quality of HD water to ensure that it meets the recommended standards. The objective of this study was to evaluate the microbial quality of HD water in Lagos, Nigeria. Four sets of pre-and post-treatment water samples, 20 mL each, were collected from six HD centers in Lagos and tested for microbial contamination using the molten Tryptic soy agar in accordance with Association for Advancement of Medical Instrumentation (AAMI) and European Best Practice Guidelines (EBPG). Pyrogen tests were also conducted on pre-and post-treatment samples using standard technique. Information on water treatment modalities, maintenance practices and quality control measures in each center were obtained using a questionnaire. All centers use treated water for HD purpose. None of the HD centers met EBPG/AAMI guidelines for microbial contaminants as the mean levels of Escherichia coli in both feed and treated water were 441.7 ± 87.90 and 168.5 ± 64.03, respectively. E. coli was the commonest organism isolated in both feed and treated water in all the centers. HD water quality is still a neglected problem in our environment and more efforts are required to ensure good water quality for HD purpose.