How does copper kill bacteria?

Q: How does copper kill bacteria?

A: Copper is an essential nutrient for humans as well as bacteria, but in high doses, copper ions can cause a series of negative events in bacterial cells. The precise chemical and molecular mechanisms responsible for copper’s antimicrobial capabilities are still being researched, however, several theories exist. They include concepts that elevated copper levels:

1. Rupture the cell membrane wall, leading to leakage of specific essential cell nutrients, such as potassium and glutamate, and subsequent cell death.

2. Disrupt osmotic pressure (osmotic balance), weakening the cell wall and allowing contents to leak out.

3. Bind to proteins that do not require copper for their function. So while copper is necessary for many protein functions, in excess situations, this “inappropriate” binding leads to loss-of-function of the protein, and/or breakdown of the protein into nonfunctional portions.

4. Cause oxidative stress and the generation of hydrogen peroxide. Under these conditions, copper participates in the so-called Fenton-type reaction—a chemical reaction causing oxidative damage to the cell.

5. “Steal” electrons from the lipids in the cell membrane, causing oxidative degradation, which leads to cell death. (Lipid peroxidation)

While the exact mechanism by which copper kills bacteria is still unknown, the laboratory data on copper’s effectiveness is compelling. CuVerro® alloys can be incorporated into a range of health care equipment and furnishings, providing an active surface that kills greater than 99.9% of bacteria within 2 hours.

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