Water treatment and monitor disinfection (original) (raw)
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Effects of biofilm formation on haemodialysis monitor disinfection
Nephrology Dialysis Transplantation, 2003
Background. Biofilms are composed of communities of micro-organisms adhering to essentially any surface. We evaluated whether biofilm formation in the hydraulic circuit of a purposely contaminated haemodialysis monitor would modify the efficacy of different disinfection modalities against bacteria and endotoxin concentrations. Methods. A water-borne Pseudomonas aeruginosa (10 9 ) suspension was recirculated for 1 h and was left standing for 72 h (stationary phase) in the hydraulic circuit of the monitor. The monitor was then washed and disinfected by different physical (heat, 85 C) or chemical (hypochlorite or peracetic acid) disinfection modalities (protocol A). In protocol B, the bacterial suspension was also recirculated for 1 h, but the monitor was then immediately washed and disinfected by different chemical disinfection modalities (hypochlorite or peracetic acid). Results. Biofilm formation was revealed by scanning and confocal laser electron microscopy after the stationary phase (protocol A), but was absent when the monitor was immediately washed and disinfected (protocol B). In the presence of biofilm (protocol A), heat in association with citric acid was the most effective modality for reducing both colony forming units and endotoxin concentrations, whereas heat by itself was the least effective method of disinfection. Dwelling (60 h) with diluted peracetic acid completely prevented the formation of biofilm. In the absence of biofilm (protocol B), chemical disinfection proved to be effective against both colony forming units and endotoxin concentrations. Conclusions. We found that biofilm formation may markedly reduce the efficacy of presently available disinfection modalities. Therefore, different disinfection modalities and the combined action of descaling (by citric acid) and disinfection (physical/chemical agents) should be used periodically in haemodialysis monitors. In addition, dwelling with diluted peracetic acid should be adopted whenever monitors are not in use.
Journal of basic and clinical pharmacy, 2014
Cross infection remains one of the major challenges in the dental profession, especially in field settings. Transmission of hepatitis B, hepatitis C, and human immunodeficiency virus have raised a major concern for patients and dental staff. These risks can be eliminated by effective sterilization and disinfection techniques. The aim was to compare the disinfecting efficacy of three chemical disinfectants on contaminated diagnostic instruments. This was a randomized, cross over trial conducted among three participants selected from a research laboratory, Bhopal, Madhya Pradesh, India. The study participants were examined 4 times on different days. Each time, the coded mouth mirrors of different make were used, and the disinfection was accomplished using coded disinfectants. The reduction in total viable count was compared between the three groups (2% glutaraldehyde, 6% hydrogen peroxide (H2O2) and 99.9% ethyl alcohol) with distilled water as negative control and autoclaving as a pos...
Prevent infection linked to the dialysis water in a hemodialysis center in Fez city (Morocco)
Pan African Medical Journal, 2013
Introduction: 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.
BDJ Open, 2016
This in vitro laboratory study compared the efficacy of water, sodium percarbonate (SPC) and chlorine dioxide (ClO 2) solutions in the disinfection of dental unit water lines (DUWLs). MATERIALS AND METHODS: New DUWL tubes were cut, split open, and mono-culture and mixed-culture biofilms of Staphylococcus aureus, Enterococcus faecalis and Streptococcus mutans were grown. Harvested biofilms from the sectioned DUWL tubes were exposed to sterile distilled water, SPC or 5 and 10 p.p.m. ClO 2 in both a stationary phase and through a constant flow. Bacterial counts were compared using the Kruskal-Wallis nonparametric rank test. RESULTS: In the mono-culture biofilms, SPC, 5 and 10 p.p.m. ClO 2 significantly reduced all the test organisms (P o 0.01). However, no significant difference was found between SPC and ClO 2. In the mixed-culture biofilms exposed to disinfectant without flow, ClO 2 significantly reduced the biofilm (P = 0.02) compared with water and SPC. Similarly, in the constant flow study, ClO 2 proved to be superior to water. CONCLUSION: At low concentrations, ClO 2 with and without flow significantly reduced the mixed-culture biofilm grown in vitro on the sections of the DUWL tubes. Therefore, it has the potential to be used in the patient treatment water, as it is potable at these concentrations, and to decontaminate and limit the biofilm formation in the water lines.
Environmental Contaminants in Hospital Settings and Progress in Disinfecting Techniques
BioMed Research International, 2013
Medical devices, such as stethoscopes, and other objects found in hospital, such as computer keyboards and telephone handsets, may be reservoirs of bacteria for healthcare-associated infections. In this cross-over study involving an Italian teaching hospital we evaluated microbial contamination (total bacterial count (TBC) at 36 ∘ C/22 ∘ C, Staphylococcus spp., moulds, Enterococcus spp., Pseudomonas spp., E. coli, total coliform bacteria, Acinetobacter spp., and Clostridium difficile) of these devices before and after cleaning and differences in contamination between hospital units and between stethoscopes and keyboards plus handsets. We analysed 37 telephone handsets, 27 computer keyboards, and 35 stethoscopes, comparing their contamination in four hospital units. Wilcoxon signed-rank and Mann-Whitney tests were used. Before cleaning, many samples were positive for Staphylococcus spp. and coliforms. After cleaning, CFUs decreased to zero in most comparisons. The first aid unit had the highest and intensive care the lowest contamination ( < 0.01). Keyboards and handsets had higher TBC at 22 ∘ C ( = 0.046) and mould contamination ( = 0.002) than stethoscopes. Healthcare professionals should disinfect stethoscopes and other possible sources of bacterial healthcare-associated infections. The cleaning technique used was effective in reducing bacterial contamination. Units with high patient turnover, such as first aid, should practise stricter hygiene.
Journal of Hospital Infection, 2017
Background: Patients receiving haemodialysis are exposed to a large volume of dialysis fluid. The Italian Society of Nephrology (ISN) published guidelines and microbial quality standards on dialysis water (DW) and solutions to ensure patient safety. Aim: Aim of the study was to identify microbial and chemical hazards and to evaluate disinfection treatments quality in DW plants. Methods: In the years 2015 and 2016 water networks and DW plants (closed loop and online monitors) of nine dialysis wards of Italian hospitals, hosting 162 dialysis beds overall, were sampled on a monthly basis to determine the parameters provided by ISN guidelines. Chlorinated drinking water was desalinated by reverse osmosis and distributed to the closed loop which feeds all online monitors. Disinfection with peracetic acid was performed in all DW plants on a monthly basis. Findings: During the entire study period of 24 months 7 out of 9 DW plants (78%) recorded negative results for all investigated parameters. A closed loop contamination of Burkholderia cepacia was detected in a DW plant from January 2015 to March 2015. Pseudomonas aeruginosa was isolated from March 2016 to May 2016 in the closed loop of another DW plant. These microbial contaminations were eradicated by shock disinfection with sodium hypochlorite and peracetic acid, followed by water flushing. Conclusion: Our results highlight the importance of chemical and physical methods of DW disinfection. The maintenance of control measures in water plants hosted in dialysis wards ensures a microbial risk reduction for all dialysis patients.