Abstract
Silver ions have been widely used as disinfectants that inhibit bacterial growth by inhibiting the essential enzymatic functions of the microorganism via interaction with the thiol-group of l-cysteine. However, silver-ion-mediated perturbation of the bacterial respiratory chain has raised the possibility of reactive oxygen species (ROS) generation. We used bacterial reporter strains specifically responding to superoxide radicals and found that silver-ion-mediated ROS-generation affected bactericidal activity. Almost half the log reduction in Escherichia coli and Staphylococcus aureus populations (model strains for gram negative and positive bacteria, respectively) caused by silver-ion disinfection was attributed to ROS-mediated bactericidal activity. The major form of ROS generated was the superoxide-radical; H2O2 was not induced. Furthermore, silver ions strongly enhanced paraquat-induced oxidative stress, indicating close correlation and synergism between the conventional and ROS-mediated silver toxicity. Our results suggest that further studies in silver-based disinfection systems should consider the oxygen concentration and ROS reaction.
Original language | English |
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Pages (from-to) | 1027-1032 |
Number of pages | 6 |
Journal | Water Research |
Volume | 43 |
Issue number | 4 |
DOIs | |
Publication status | Published - 2009 Mar |
Bibliographical note
Funding Information:The authors wish to acknowledge the financial support of the Seoul R & D Program (10538), through the Institute of Bioengineering, Seoul National University, Seoul, Korea. This work was also supported by a Pusan National University research grant, 2006. These contributions are greatly appreciated.
Keywords
- Bactericidal
- E. coli
- ROS (reactive oxygen species)
- S. aureus
- Silver
- Superoxide
ASJC Scopus subject areas
- Ecological Modelling
- Water Science and Technology
- Waste Management and Disposal
- Pollution