Avoiding toxicity from water-borne contaminants in hemodialysis: new challenges in an era of increased demand for water

Blood Aluminum Levels in Patients with Hemodialysis and Peritoneal Dialysis

Background. This retrospective observational study attempted to examine the prevalence of abnormal blood aluminum levels in dialysis patients, and to explore the association of pathogenic factors, such as demographic, clinical, laboratory as well as the use of phosphate binding drugs, drugs for secondary hyperparathyroidism and erythropoiesis-stimulating drugs with the blood aluminum levels. Methods. The study included 1175 patients (874 hemodialysis and 301 peritoneal dialysis), recruited from Chang Gung Memorial Hospital in November 2020. Patients were stratified into two groups by their blood aluminum levels, as normal (<2 µg/dL, n = 1150) or abnormal (≥2 µg/dL, n = 25). Results. The patients aged 60.4 ± 13.2 years and were dialyzed for 8.6 ± 8.1 years. The average blood aluminum level was 1.0 ± 0.4 µg/dL. Patients with abnormal blood aluminum levels received more sevelamer than patients with normal blood aluminum level (p = 0.014). Patients with abnormal blood aluminum levels had higher platelet count (p = 0.001), triglyceride (p < 0.001) and total iron binding capacity (p = 0.003) than patients with normal blood aluminum levels. Moreover, the cardiothoracic ratio was higher in patients with abnormal blood aluminum levels than patients with normal blood aluminum levels (p = 0.003). Conclusions. The prevalence of abnormal blood aluminum levels was low at 2.2%. Nevertheless, the linking of cardiothoracic ratio of more than 0.5 as well as elevated blood platelet count and triglyceride level with blood aluminum levels are interesting, and warranted more researches in this area.

Identification and assessment of antimicrobial resistance bacteria in a hemodialysis water treatment system

The water treatment process is a vital factor for hemodialysis (HD) patients. This study aimed to assess the degree of contamination of HD water by bacteria at the HD center of Mohammedia, Morocco, in addition to evaluating the antimicrobial resistance of isolated bacteria. Fifty-four water samples were taken, the appropriate cultures were used to isolate the pathogenic bacteria, which were identified biochemically and molecularly by 16S RNA sequencing. Their susceptibility to antimicrobial drugs was determined by the disk diffusion method. Approximately 5.5% of water samples were above the norm. The isolated bacteria that colonized the HD systems were mostly Gram-negative bacilli, such as Stenotrophomonas maltophilia, Pseudomonas spp., and Burkholderia cepacian. Results of the antibiotics test showed remarkable resistance levels. Among Pseudomonas spp. and S. maltophilia, 10 strains were classified as multidrug-resistant (MDR), and 4 as extensively drug-resistant (XDR). The diversity of bacterial strains isolated in the water used for HD treatments, and their worrying resistance levels pose a significant risk to patients. For these reasons, an urgent need for periodic microbiological monitoring of water after each treatment step must be applied, and the treatment process should also be optimized.

Novel Use of Premixed Dialysate Bags during Water Supply Interruption in Acute Hospital Setting

Patients on dialysis are exposed to large amounts of water during conventional intermittent hemodialysis; hence, there are strict regulations regarding the quality of water used to prepare dialysate. Occasionally, water systems fail due to natural disasters or structural supply issues, such as water-main breaks or unplanned changes in municipal or facility water quality. It is critical to regularly monitor and immediately recognize such a failure and take steps to avoid exposing the patients to contaminants. In addition to the recognition of the problem, the ability to pivot and continue to provide safe treatment to inpatients who are dependent on dialysis is essential, both from an ultrafiltration and a clearance standpoint. At our hospital, an unforeseen water disruption occurred and we were able to continue to provide KRT with premade, bagged dialysate to mitigate the effect on our patients on dialysis. This is a novel method using available machines and dialysate, which we normally stock for continuous KRT, for short dialysis sessions. The methodology is similar to that which has been widely used for short daily home hemodialysis with low dialysate flow rate. Because this situation occurred in the midst of the SARS-CoV-2 pandemic, we had to be mindful of dialysate volumes and staffing time. Here, we present our investigation into the cause of the water-system failure and how we quickly implemented the alternative dialysis method. Short dialysis with low-flow dialysate will not deliver the same Kt/V per session as standard dialysis; however, this method was successfully implemented and tailored with adjustments for patients requiring higher clearance for specific indications, such as severe hyperkalemia.

Transfer of low-molecular weight single-stranded DNA through the membrane of a high-flux dialyzer

PURPOSE

Microbial contamination is often present in dialysate used for hemodialysis. Small single-stranded bacterial DNA sequences are capable of activating human inflammatory pathways, through mechanisms that include the Toll-like-receptor 9, and dialysis patients frequently show severe inflammation. Since these molecules have been found in dialysate and in patients' bloodstreams, we studied the potential of low-molecular weight DNA sequences, of the same structure as found in bacteria, to cross from the dialyzer circuit to the blood circuit of a dialysis filter.

METHODS

The mass transfer of DNA fragments across a high-flux dialyzer was evaluated with an in vitro dialysis model, in both conventional dialysis and pure convection mode. Measurement of DNA was performed by HPLC.

RESULTS

In dialysis mode, these mass transfer coefficients were calculated for different single-stranded DNA chain lengths: 5-bases = 28.5%, 9-bases = 20.5%, 20-bases = 9.4%, 35-bases = 2.4%, 50-bases and 100-bases, no transfer detected. In convection mode, these sieving coefficients were calculated: 5-bases = 1.0, 9-bases = 1.0, 20-bases = 0.68, 35-bases = 0.40, 50-bases = 0.17, 100-bases, no convective transfer detected. The physical size of DNA molecules could be the major factor that influences their movement through dialyzer pores.

CONCLUSIONS

This study establishes that significant transfer across the dialyzer may occur with single-stranded DNA in the size range of 20-bases or less. These findings need to be confirmed with an in vitro whole blood model and with clinical investigations. Previous studies have described the clinical benefits of achieving high-purity dialysate. Precautions are warranted to minimize the presence of these DNA compounds in fluids utilized for hemodialysis treatment.

Prevent infection linked to the dialysis water in a hemodialysis center in Fez city (Morocco)

Background

Water treatment systems are a critical variable in dialysis therapy. Rigorous control of hemodialysis water quality is particularly important in order to guarantee a better quality of life of the hemodialysis patients. The objective of the study was to evaluate the chemical, microbiological quality and antimicrobial resistance of bacteria isolated from water and dialysate in a public HD center.

Methods

Fifty five samples of water and dialysate were collected weekly over a period of 4 months. The samples were collected from 4 points in the distribution loop. The microbiological and chemical analyses were performed according to our national standards. Antimicrobial susceptibilities patterns of isolated bacteria were determined by disk diffusion method.

Results

The chemical and microbiological parameters in all dialysis water and dialysate samples are in accordance with national standards. However, 70 Gram-negative bacteria were identified: Pseudomonas sp, Ochrobactrum antropi and Burkholderia cepacia, isolated at 52.8%, 12.8% and 17% simultaneously. Fourteen per cent of the isolates were resistant to three or more antibiotics. All resistant bacteria belong to the genus of Pseudomonas, 80% were resistant to tetracycline and to co-trimoxazole, 30% to ceftazidime. No colistin and imipenem resistance was observed.

Conclusion

To avoid a health risk due to bacterial contamination, an adequate system for water treatment, disinfection of the hemodialysis system and microbiological monitoring of the water and dialysate are necessary.

Hemodialysis and water quality

Over 383,900 individuals in the U.S. undergo maintenance hemodialysis that exposes them to water, primarily in the form of dialysate. The quality of water and associated dialysis solutions have been implicated in adverse patient outcomes and is therefore critical. The Association for the Advancement of Medical Instrumentation has published both standards and recommended practices that address both water and the dialyzing solutions. Some of these recommendations have been adopted into Federal Regulations by the Centers for Medicare and Medicaid Services as part of the Conditions for Coverage, which includes limits on specific contaminants within water used for dialysis, dialysate, and substitution fluids. Chemical, bacterial, and endotoxin contaminants are health threats to dialysis patients, as shown by the continued episodic nature of outbreaks since the 1960s causing at least 592 cases and 16 deaths in the U.S. The importance of the dialysis water distribution system, current standards and recommendations, acceptable monitoring methods, a review of chemical, bacterial, and endotoxin outbreaks, and infection control programs are discussed.