Quality of dialysis water and dialysate in haemodialysis centres: Highlight for occurrence of non-fermenting gram-negative bacilli

Abstract

Aims To evaluate the physicochemical and microbiological quality of dialysis water and dialysate samples from haemodialysis centres. Methods and Results Samples were fortnightly collected from three haemodialysis centres in Bauru City, Brazil, between July 2017 and June 2018, at the stages of post‐reverse osmosis, reuse and dialysate. Analyses included determination of conductivity, fluoride, nitrate and sulphate; test for total coliform bacteria; count of heterotrophic bacteria; count and identification of non‐fermenting gram‐negative bacilli (NFGNB); drug susceptibility test; biofilm formation capacity; and genetic similarity among some isolated NFGNB. Of the analysed samples, only 4/72 (5.6%) had conductivity values ≥10 mS/cm, 4/216 (1.9%) presented total coliforms and 1/216 (0.5%) had heterotrophic bacteria count >100 CFU/ml. NFGNB were isolated from 99/216 (45.8%) samples, and the major identified micro‐organisms included Herbaspirillum aquaticum/huttiense, Brevundimonas aurantiaca, Cupriavidus metallidurans, Pseudomonas aeruginosa and Ralstonia insidiosa. Isolates of P. aeruginosa and Burkholderia cepacia complex were sensitive to most antimicrobials and, together with isolates of Ralstonia insidiosa and Ralstonia pickettii, showed strong biofilm formation capacity. Some isolates expressed the same electrophoretic profile on pulsed‐field gel electrophoresis, indicating the persistence of bacterial clones in the systems over time. Conclusions NFGNB were observed in several dialysis water and dialysate samples from all investigated centres, which may represent a risk to the health of patients. Significance and Impact of the Study Regular inclusion of actions for NFGNB control and monitoring in haemodialysis fluids are suggested for greater safety of the dialytic process.

Physical-chemical and microbiological characterization of water destined to hemodialysis

“…The results revealed the presence of the genera Herbarpirillum, Brevundimonas, Ralstonia, and Burkholderia, aligning with the findings of the current study. Also, de Jesus et al (2022) studying hemodialysis units in Rio de Janeiro, Brazil, employing biochemical methods for bacterial identification, corroborated the findings of Anversa et al (2022). It is noteworthy that the common presence of the species Pseudomonas aeruginosa, widely documented in various Brazilian studies using biochemical techniques (Lima et al, 2005;Borges et al, 2007;de Jesus, et al, 2017;; MALDI-TOF (Anversa et al, 2022); and molecular biology identification methods (Montanari et al, 2009), was not detected in the present investigation.…”

“…Most of the bacteria species that were isolated belong to the nonfermenting gramnegative category, with the exception of Serratia marcescens, which is part of the fermenting gram-negative group. The gram-negative bacteria, especially the nonfermenting ones, are the most common microbiological contaminant found in hemodialysis water (Chen et al, 2017;de Jesus, et al, 2017;Anversa et al, 2022;Chaoui et al, 2022). In the study conducted by Anversa et al (2022) in hemodialysis units in São Paulo, Brazil, MALDI-TOF methodology was employed, resembling the approach used in the present research.…”

“…The gram-negative bacteria, especially the nonfermenting ones, are the most common microbiological contaminant found in hemodialysis water (Chen et al, 2017;de Jesus, et al, 2017;Anversa et al, 2022;Chaoui et al, 2022). In the study conducted by Anversa et al (2022) in hemodialysis units in São Paulo, Brazil, MALDI-TOF methodology was employed, resembling the approach used in the present research. Distinctively, filtration treatment was incorporated into the water samples.…”

“…Microbiological contaminants can also be found in water, and their presence is often associated with failures of the dialysis water treatment and distribution system (Ferreira et al 2015;Ferreira et al 2020). Among the most frequent, gram-negative bacteria (Okunola and Olaitan, 2016;Anversa et al, 2022;Chaoui et al, 2022), that may be associated with infections in hemodialysis patients (Tejera et al, 2016;Thet et al, 2019), can be highlighted. These bacteria can also represent a serious threat to patients due to their ability to form biofilms and develop antibiotic resistance.…”

Transcriptomic and metabolomic analyses to study the key role by which Ralstonia insidiosa induces Listeria monocytogenes to form suspended aggregates

“…As an environmental bacterium, R. insidiosa can be found in a wide range of aqueous environments such as industrial water, laboratory pure water, and hospital water systems, as well as in rivers, ponds, and soils. It is equally well suited to survive in low-nutrient surroundings (Anversa et al, 2022 ). Current studies show that R. insidiosa isolated from the fresh fruit processing environment plays a bridging role in the biofilm formation of many foodborne pathogens such as Salmonella enterica, Listeria monocytogenes , and Escherichia coli (Liu et al, 2015 , 2016 ).…”