Killing of enteric bacteria in drinking water by a copper device for use in the home: laboratory evidence

Sudha, V.; Singh, Kuldeep; Prasad, SR; Venkatasubramanian, Padma

doi:10.1016/j.trstmh.2009.01.019

Cited by 59 publications

(38 citation statements)

References 7 publications

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“…Total inactivation was observed within 48 h storage in a brass vessel (Tandon et al 2005). Similarly, inactivation of E. coli, Salmonella enterica serovar Typhi and Vibrio cholerae after overnight water storage in copper pots has been reported recently by Sudha et al (2009), based on conventional aerobic counts. Recent studies (Sharan et al 2010) have demonstrated the effect of temperature and pH on antibacterial action of copper against E. coli stored in pure water, with the observation that fastest inactivation took place at elevated temperatures and at pH furthest from neutrality.…”

Section: Introductionsupporting

confidence: 53%

Inactivation and sub-lethal injury of Escherichia coli in a copper water storage vessel: effect of inorganic and organic constituents

Sharan

Chhibber

Attri

et al. 2010

Antonie van Leeuwenhoek

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This study provides information on the effects of inorganic and organic constituents on inactivation and sub-lethal injury of Escherichia coli in water stored in a copper vessel. E. coli suspensions were stored for up to 24 h in copper vessels containing one of the following dissolved constituents at 1 g/l: salts of inorganic ions, carbohydrates, proteins and complex natural organic mixtures. Samples were surface plated onto (i) nutrient agar, incubated under standard aerobic conditions to provide conventional counts for uninjured bacteria count and onto (ii) nutrient agar plates with 0.5 g/l sodium pyruvate incubated under anaerobic conditions to enumerate sub-lethally injured (oxygen-sensitive) bacteria alongside their healthy counterparts. The concentration of dissolved copper in the stored water was determined using atomic absorption spectrophotometry. The addition of chloride salts resulted in a faster inactivation of E. coli compared to pure water with no dissolved additives, irrespective of the counterion. In contrast, a slower inactivation was observed in the presence of Na(2)SO(4), NaNO(3) and NaNO(2) when compared to NaCl. Addition of the carbohydrates glucose, lactose and starch gave broadly similar results to those obtained using unsupplemented water. However, the addition of amino acids, proteins, humic acid or complex organic mixtures caused a dramatic decrease in inactivation of E. coli, with evidence of a greater number of sub-lethally injured bacteria than was seen with other added constituents. The amount of copper was highest in stored water containing amino acids and complex organic constituents, with the slow inactivation most likely to be due to complex formation between leached copper and these organic constituents. The present study clearly demonstrates that water composition, particularly natural organic constituents, has a substantial impact on the antibacterial effectiveness and dissolved copper concentration of water stored in copper vessels and that both aspects will need to be considered in terms of their impact on the practical use of copper-based systems for small-scale water treatment.

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Section: Introductionsupporting

confidence: 53%

Inactivation and sub-lethal injury of Escherichia coli in a copper water storage vessel: effect of inorganic and organic constituents

Sharan

Chhibber

Attri

et al. 2010

Antonie van Leeuwenhoek

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“…Similarly, Brick et al (2004) have also described significantly decreased contamination due to faecal coliform bacteria and E. coli in household waters kept in brass storage vessels, both under field conditions and in the laboratory. Sudha et al (2009) have reported that water stored overnight in copper pots gave no counts for E. coli, Salmonella enterica serovar Typhi and Vibrio cholerae, demonstrating inactivation of these bacteria. Equivalent studies of the inactivation of bacteria on copper surfaces (http://www.copper.org/antimicrobial/home page.html) are also consistent with these findings.…”

Section: Discussionmentioning

confidence: 99%

Inactivation and injury of Escherichia coli in a copper water storage vessel: effects of temperature and pH

Sharan

Chhibber

Attri

et al. 2009

Antonie van Leeuwenhoek

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Copper has been used as a disinfectant since ancient times and recent research has demonstrated that antimicrobial copper surfaces may have practical applications in healthcare and related areas. The present study was carried out to establish the effects of temperature and pH on inactivation and sub-lethal injury of Escherichia coli in water stored in a copper vessel, to determine the operational limits of the process in terms of these variables. To investigate the effects of temperature, a bacterial suspension at pH 7.0 was stored for up to 48 h in copper vessels at 5, 15, 25 and 35 degrees C. For pH, a bacterial suspension was stored at 30 degrees C for up to 48 h in copper vessels at pH 6.0, 7.0, 8.0 and 9.0. Both temperature and pH had substantial effects on inactivation and injury, with the fastest inactivation observed at elevated temperature and at pH values furthest from neutrality, while the greatest amount of sub-lethal injury, manifest as sensitivity to conventional aerobic enumeration, was observed at a temperature of 35 degrees C. These findings have important implications for the practical application of copper-based water disinfection methods, in terms of their likely efficacy under environmental conditions.

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“…A 1983 report documenting the beneficial effects of using brass and bronze on doorknobs to prevent the spread of microbes in a hospitals remained largely unnoticed (18). Similarly, the idea of using copper vessels to render water drinkable has been revived only very recently as a low-cost alternative for developing countries (37). Currently, there is an intense interest in the use of copper as a selfsanitizing material, and many recent publications deal with mechanistic aspects of "contact killing" (contact-mediated killing) by copper.…”

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confidence: 99%

Metallic Copper as an Antimicrobial Surface

Grass

Rensing

Solioz

2011

Appl Environ Microbiol

1,295

1,037

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3Bacteria, yeasts, and viruses are rapidly killed on metallic copper surfaces, and the term "contact killing" has been coined for this process. While the phenomenon was already known in ancient times, it is currently receiving renewed attention. This is due to the potential use of copper as an antibacterial material in health care settings. Contact killing was observed to take place at a rate of at least 7 to 8 logs per hour, and no live microorganisms were generally recovered from copper surfaces after prolonged incubation. The antimicrobial activity of copper and copper alloys is now well established, and copper has recently been registered at the U.S. Environmental Protection Agency as the first solid antimicrobial material. In several clinical studies, copper has been evaluated for use on touch surfaces, such as door handles, bathroom fixtures, or bed rails, in attempts to curb nosocomial infections. In connection to these new applications of copper, it is important to understand the mechanism of contact killing since it may bear on central issues, such as the possibility of the emergence and spread of resistant organisms, cleaning procedures, and questions of material and object engineering. Recent work has shed light on mechanistic aspects of contact killing. These findings will be reviewed here and juxtaposed with the toxicity mechanisms of ionic copper. The merit of copper as a hygienic material in hospitals and related settings will also be discussed.

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Killing of enteric bacteria in drinking water by a copper device for use in the home: laboratory evidence

Cited by 59 publications

References 7 publications

Inactivation and sub-lethal injury of Escherichia coli in a copper water storage vessel: effect of inorganic and organic constituents

Inactivation and sub-lethal injury of Escherichia coli in a copper water storage vessel: effect of inorganic and organic constituents

Inactivation and injury of Escherichia coli in a copper water storage vessel: effects of temperature and pH

Metallic Copper as an Antimicrobial Surface

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