How Does Silver Kill Bacteria?

Silver (chemical symbol, Ag) has been used for many years as an antibacterial agent. Compounds within silver naturally eliminate bacteria and inhibit their growth. New technology has made it possible to create silver-based compounds with which to coat everyday items with, helping to prevent the spreading of bacteria. In 2003, the U.S. Food and Drug Administration approved the use of silver in the food industry, which further helps to prevent bacterial epidemics such as infection with Escherichia coli.

How it Works

• Hospitals use a form of antimicrobial silver-based compound, called Ag ions, made up of 5 percent silver contained within a nonactive crystalline carrier. When this compound is exposed to a small amount of moisture, it releases Ag ions, which eliminate bacterial growth on surfaces by killing existing microbes and preventing new ones from forming. This action can happen on many different types of surfaces like door handles, pens and even athletic shoes. While the compound is tough on germs, it is safe to use and barely toxic. "It's less toxic than table salt and less irritating than talcum powder," says Jeffrey Trologo, chief technology officer at AgION Technologies. "Ultimately we hope this will result in less infections and actually better outcomes for the patients."

History

• Silver has been used for centuries as an antimicrobial and antibacterial agent. It has natural germicidal properties that help inhibit the growth of harmful bacteria. The ancient Egyptians and Greeks used silver holders for water to keep it fresh and drinkable. The discovery or antibiotics took away some of the limelight from silver, but recent concern over antibiotic-resistant super organisms has brought it back to popularity.

New Technology and Uses

• "With increasing uses of silver in many forms including sprays, gels and coatings, the use of silver as an antimicrobial agent continues to grow not only in hospitals and other patient treatment centers, but also in public areas such as restaurants, airports and institutional buildings," says Jeffrey Ellis, senior technology consultant for The Silver Institute. Other uses for silver include coatings for sinks, flooring, bed rails, stethoscopes, pens, catheters and other small portable items. Silver can also be embedded into textile products like hospital gowns and wound coverings to help prevent bacterial infections.

Risks

• If ingested in small amounts, silver is harmless to the body; however, like most metals, large doses can be dangerous or fatal if ingested. Silver and other compounds that contain silver can be absorbed through the body's circulatory system, resulting in argyria, or a bluish discoloration of the skin, eyes, and other soft tissues of the body. This condition is harmless, but it is usually permanent.