The interaction of silver ions and hydrogen peroxide in the inactivation of E. coli: a preliminary evaluation of a new long acting residual drinking water disinfectant

1995 ◽  
Vol 31 (5-6) ◽  
pp. 123-129 ◽  
Author(s):  
Rami Pedahzur ◽  
Ovadia Lev ◽  
Badri Fattal ◽  
Hillel I. Shuval
Keyword(s):  
Hydrogen Peroxide ◽  
Drinking Water ◽  
Distribution Systems ◽  
Residual Effect ◽  
Silver Ions ◽  
Product Formation ◽  
Preliminary Evaluation ◽  
E Coli ◽  
The Usa ◽  
K 12

The inactivation efficiencies of silver ions, hydrogen peroxide and their combination was studied as part of a performance evaluation of the combined disinfectant for drinking water applications. The major advantages of such combined disinfectant include, low toxicity of its components, long lasting residual effect and low disinfection by product formation. Specific strains of E. coli (E. coli-B (SR-9) and E. coli K-12) were used in this study as target microorganisms and the separate and combined inactivation efficiencies of silver and hydrogen peroxide were evaluated at different concentrations and exposure durations. Both, silver and hydrogen peroxide exhibited a significant inactivation performance even at concentrations that do not pose any health risk according to the EEC, WHO and the USEPA (the USEPA Maximum Contaminant Level (MCL) of silver is 90 ppb, and currently, there is no MCL for hydrogen peroxide but it is approved as a food additive in the USA). Combinations of 1:1000 silver:hydrogen peroxide (w) exhibited higher inactivation performance as compared with each of the disinfectants alone and in some cases a synergistic effect was observed, i.e., the combined disinfectant exhibited higher inactivation performance than the sum of the inactivation levels of the separate disinfectants. Thus, for example, one hour exposure to 30 ppb silver, 30 ppm hydrogen peroxide and their combination yielded 2.87, 0.65 and 5 logs of inactivation respectively. While the rate of inactivation shown by this combined disinfectant, now available commercially in a stabilized formulation is relatively slow, it may well hold promise as a secondary disinfectant providing long lasting residuals and biofilm control required for distribution systems. Its disinfection action may be similar to chloramines, the use of which has been recently outlawed in France and in Germany and which are now under careful scrutiny in other countries due to the formation of undesirable by-products.

Potentiation by L-cysteine of the bactericidal effect of hydrogen peroxide in Escherichia coli

1982 ◽  
Vol 152 (1) ◽  
pp. 81-88
Author(s):  
E H Berglin ◽  
M B Edlund ◽  
G K Nyberg ◽  
J Carlsson
Keyword(s):  
Escherichia Coli ◽  
Hydrogen Peroxide ◽  
Metal Ion ◽  
Chelating Agent ◽  
Fold Increase ◽  
Bactericidal Effect ◽  
Anaerobic Conditions ◽  
Dna Breakage ◽  
E Coli ◽  
K 12

Under anaerobic conditions an exponentially growing culture of Escherichia coli K-12 was exposed to hydrogen peroxide in the presence of various compounds. Hydrogen peroxide (0.1 mM) together with 0.1 mM L-cysteine or L-cystine killed the organisms more rapidly than 10 mM hydrogen peroxide alone. The exposure of E. coli to hydrogen peroxide in the presence of L-cysteine inhibited some of the catalase. This inhibition, however, could not fully explain the 100-fold increase in hydrogen peroxide sensitivity of the organism in the presence of L-cysteine. Of other compounds tested only some thiols potentiated the bactericidal effect of hydrogen peroxide. These thiols were effective, however, only at concentrations significantly higher than 0.1 mM. The effect of L-cysteine and L-cystine could be annihilated by the metal ion chelating agent 2,2'-bipyridyl. DNA breakage in E. coli K-12 was demonstrated under conditions where the organisms were killed by hydrogen peroxide.

scholarly journals Effect of Chloride Ions on the Point-of-Use Drinking Water Disinfection Performance of Porous Ceramic Media Embedded with Metallic Silver and Copper

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1625
Author(s):  
Rekha Singh ◽  
Woohang Kim ◽  
James A. Smith
Keyword(s):  
Drinking Water ◽  
Porous Ceramic ◽  
Chloride Ion ◽  
Silver Ions ◽  
Chloride Ions ◽  
Ion Concentration ◽  
Metallic Silver ◽  
E Coli ◽  
Ion Concentrations ◽  
Copper Release

This study quantifies the effects of chloride ions on silver and copper release from porous ceramic cubes embedded with silver and copper and its effect on E. coli disinfection in drinking water. Log-reduction of E. coli by silver ions decreased after 4 h of contact time as the chloride ion concentration increased from 0 to 250 mg/L but, it was not changed by copper ions under the same conditions. For silver addition by silver-ceramic cubes, log reductions of E. coli decreased sharply from 7.2 to 1.6 after 12 h as the chloride concentration increased from 0 to 250 mg/L. For the silver-ceramic cube experiments, chloride ion also reduced the total silver concentration in solution. After 24 h, total silver concentrations in solution decreased from 61 µg/L to 20 µg/L for corresponding chloride ion concentrations. According to the MINTEQ equilibrium model analysis, the decrease in disinfection ability with silver embedded ceramic cubes could be the result of precipitation of silver ions as silver chloride. This suggests that AgCl was precipitating within the pore space of the ceramic. These results indicate that, although ionic silver is a highly effective disinfectant for E. coli, the presence of chloride ions can significantly reduce disinfection efficacy. For copper-ceramic cubes, log reductions of E. coli by copper embedded cubes increased from 1.2 to 1.5 when chloride ion concentration increased from 0 to 250 mg/L. Total copper concentrations in solution increased from 4 µg/L to 14 µg/L for corresponding chloride ion concentrations. These results point towards the synergistic effect of chloride ions on copper oxidation as an increased concentration of chloride enhances copper release.

Silver and hydrogen peroxide as potential drinking water disinfectants: their bactericidal effects and possible modes of action

1997 ◽  
Vol 35 (11-12) ◽  
pp. 87-93 ◽  
Author(s):  
R. Pedahzur ◽  
H. I. Shuval ◽  
S. Ulitzur
Keyword(s):  
Hydrogen Peroxide ◽  
Synergistic Effect ◽  
Vibrio Fischeri ◽  
E Coli ◽  
Bactericidal Effects ◽  
Synergistic Induction ◽  
Response Systems ◽  
K 12 ◽  
Consequent Increase

Silver and hydrogen peroxide (HP) acted synergistically on the viability of E. coli K-12. In certain concentration ranges the synergistic effect amounted to about 3 logs. Toxicity process kinetics were determined by following the decrease in luminescence of a highly luminescent recombinant E. coli harbouring a plasmid carrying the whole lux system of Vibrio fischeri. As in the viability studies, silver and HP also showed a synergistic effect on in vivo luminescence, which amounted to a 2 log increase in toxicity. A similar phenomenon was found for silver and certain metal ions, including Cu2+, Ni2+, Zn2+ and Cd2+, where toxicity increased by a factor of 10 in the presence of sub-inhibitory concentrations of silver. To monitor the expression of different stress response systems in treated cells, we have used E. coli carrying fusions of the lux system to promoters of different stress-controlling genes. Of the fusions tested, HP substantially increased the activity of recA, katG, micF, grpE, lon, and dnaK. Silver exerted a mild effect acting only on grpE and lon promoters. When in combination, a synergistic induction of the dnaK fusion and a slightly additive effect on grpE fusion were recorded. It appears that the combined toxic effect of silver and HP may be related with damage to cellular proteins. Nevertheless, the involvement of other cellular moieties can not be ruled out. The possibility that the synergistic effect is related to chemical interactions between silver and HP and the consequent increase in their toxicity is discussed.

Chlorine sensitivity of environmental, distribution system and biofilm coliforms

1997 ◽  
Vol 35 (11-12) ◽  
pp. 289-292 ◽  
Author(s):  
D. P. Sartory ◽  
P. Holmes
Keyword(s):  
Drinking Water ◽  
River Water ◽  
Distribution System ◽  
Distribution Systems ◽  
Bulk Water ◽  
Coliform Bacteria ◽  
Environmental Distribution ◽  
River Waters ◽  
E Coli ◽  
Treated Drinking Water

Coliform bacteria, isolated from treated drinking water supplies, can be derived from a range of sources (e.g. infiltration, breakthrough at the treatment works or from the biofilm established within the pipework). The sensitivity of these bacteria to chlorine may be related to their source and metabolic status. Strains of coliforms were isolated from sewage works effluents, river and reservoir waters as well as from the bulk water and biofilms from distribution systems. These were assayed for sensitivity to free and total chlorine using two assay procedures. For E. coli, the isolates from the distribution system bulk water showed greater resistance to free chlorine than those from sewage effluents and equivalence to those from river waters. For non-E. coli coliforms (mainly strains of Klebsiella, Enterobacter and Citrobacter), those from distribution system biofilms showed the greatest sensitivity to free and total chlorine whilst those from river water had the greatest resistance.

scholarly journals Effect of Phosphorus on Survival of Escherichia coli in Drinking Water Biofilms

2007 ◽  
Vol 73 (11) ◽  
pp. 3755-3758 ◽  
Author(s):  
Talis Juhna ◽  
Dagne Birzniece ◽  
Janis Rubulis
Keyword(s):  
Escherichia Coli ◽  
Drinking Water ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution System ◽  
Phosphorus Addition ◽  
Drinking Water Distribution Systems ◽  
E Coli ◽  
Drinking Water Distribution

ABSTRACT The effect of phosphorus addition on survival of Escherichia coli in an experimental drinking water distribution system was investigated. Higher phosphorus concentrations prolonged the survival of culturable E. coli in water and biofilms. Although phosphorus addition did not affect viable but not culturable (VBNC) E. coli in biofilms, these structures could act as a reservoir of VBNC forms of E. coli in drinking water distribution systems.

scholarly journals Impact of Some Ecological Factors on Fecal Contamination of Drinking Water by Diarrheagenic Antibiotic-ResistantEscherichia coliin Zagazig City, Egypt

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Ahmed Elsadek Fakhr ◽  
Maha Kamal Gohar ◽  
Amal Hassan Atta
Keyword(s):  
Drinking Water ◽  
Population Density ◽  
Distribution Systems ◽  
Virulence Genes ◽  
Fecal Contamination ◽  
Antibiotic Sensitivity ◽  
Ecological Factors ◽  
Antibiotic Resistant ◽  
Major Health Problem ◽  
E Coli

Fecal contamination of drinking water is a major health problem which accounts for many cases of diarrhea mainly in infants and foreigners. This contamination is a complex interaction of many parameters. Antibiotic resistance among bacterial isolates complicates the problem. The study was done to identify fecal contamination of drinking water by Diarrheagenic Antibiotic-ResistantEscherichia coliin Zagazig city and to trace reasons for such contamination, three hundred potable water samples were investigated forE. coliexistence. Locations ofE. colipositive samples were investigated in relation to population density, water source, and type of water pipe. SixteenE. colistrains were isolated. Antibiotic sensitivity was done and enterotoxigenic, enteropathogenic, and enterohaemorrhagic virulence genes were investigated by PCR. Probability of fecal contamination correlated with higher population density, with increased distance from Zagazig water plant, and with asbestos cement water pipes. Resistance to at least one antimicrobial drug was found in all isolates. Virulence genes were detected in a rate of 26.27%, 13.13%, 20%, 6.67%, and 33.33% for LT, ST, stx1, stx2, and eae genes, respectively. This relatively high frequency of fecal contamination points towards the high risk of developing diarrhea by antibiotic resistant DEC in low socioeconomic communities particularly with old fashion distribution systems.

A SitABCD homologue from an avian pathogenic Escherichia coli strain mediates transport of iron and manganese and resistance to hydrogen peroxide

Microbiology ◽  
2006 ◽  
Vol 152 (3) ◽  
pp. 745-758 ◽  
Author(s):  
Mourad Sabri ◽  
Simon Léveillé ◽  
Charles M. Dozois
Keyword(s):  
Escherichia Coli ◽  
Hydrogen Peroxide ◽  
Metal Ion ◽  
Growth Promotion ◽  
Coli Strain ◽  
Transport Systems ◽  
Virulence Plasmid ◽  
E Coli ◽  
K 12 ◽  
Iron And Manganese

An operon encoding a member of the family of ATP-binding cassette (ABC) divalent metal ion transporters, homologous to Salmonella enterica SitABCD, has been identified in the avian pathogenic Escherichia coli (APEC) strain χ7122. The sitABCD genes were located on the virulence plasmid pAPEC-1, and were highly similar at the nucleotide level to the chromosomally encoded sitABCD genes present in Shigella spp. A cloned copy of sitABCD conferred increased growth upon a siderophore-deficient E. coli strain grown in nutrient broth supplemented with the chelator 2,2′-dipyridyl. Ion rescue demonstrated that Sit-mediated growth promotion of this strain was due to the transport of iron. SitABCD mediated increased transport of both iron and manganese as demonstrated by uptake of 55Fe, 59Fe or 54Mn in E. coli K-12 strains deficient for the transport of iron (aroB feoB) and manganese (mntH) respectively. Isotope uptake and transport inhibition studies showed that in the iron transport deficient strain, SitABCD demonstrated a greater affinity for iron than for manganese, and SitABCD-mediated transport was higher for ferrous iron, whereas in the manganese transport deficient strain, SitABCD demonstrated greater affinity for manganese than for iron. Introduction of the APEC sitABCD genes into an E. coli K-12 mntH mutant also conferred increased resistance to the bactericidal effects of hydrogen peroxide. APEC strain χ7122 derivatives lacking either a functional SitABCD or a functional MntH transport system were as resistant to hydrogen peroxide as the wild-type strain, whereas a Δsit ΔmntH double mutant was more sensitive to hydrogen peroxide. Overall, the results demonstrate that in E. coli SitABCD represents a manganese and iron transporter that, in combination with other ion transport systems, may contribute to acquisition of iron and manganese, and resistance to oxidative stress.

scholarly journals Development of nanosilver-coated geopolymer beads (AgGP) from fly ash and baluko shells for antimicrobial applications

2019 ◽  
Vol 268 ◽  
pp. 05003 ◽  
Author(s):  
Kimmie Dela Cerna ◽  
Jose Isagani Janairo ◽  
Michael Angelo Promentilla
Keyword(s):  
Hydrogen Peroxide ◽  
Fly Ash ◽  
Controlled Release ◽  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Antimicrobial Agents ◽  
Setting Time ◽  
Silver Ions ◽  
Foaming Agents ◽  
E Coli

Geopolymers are a class of materials formed from treating alumina (Al2O3) and silica (SiO2) containing materials with an alkali activator. They are most notable for being environmentally-friendly substitutes to Ordinary Portland Cement; however, recent findings have shown that they may have potential as support matrices for antimicrobial agents such as nanosilver, particularly with the addition of foaming agents and setting time accelerators. In this study, nanosilver-coated geopolymer beads (AgGP) were made from fly ash (FA), calcined Baluko shells or pen shells (BS), and hydrogen peroxide (H). Addition of BS and H reduces the setting time and increases the porosity of the geopolymer beads. The beads were then dipped in AgNO3 and NaBH4 respectively to provide the nanosilver coating. When immersed in water, a controlled release of silver ions leaches out from the beads, neutralizing any bacteria in the water. It was found that the AgGP removed as much as 99.96% of the E. coli in a suspension originally at 105 CFU/mL.

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