Silver has been used topically and orally to help treat wounds for over two thousand years, though the exact mechanism of how it was helping was a mystery. New research from Boston University explains silver’s antimicrobial properties and shows that when silver ions are added to antibiotics, it can be 10-1,000 times more effective than just using the antibiotic alone.
And now, for the two-millennia-old question: how does it all work? The silver itself does not kill the bacteria. It creates oxygen compounds that are quite reactive. Even small amounts of silver compromise the bacteria’s protective membrane, allowing the antibiotic to have better access to the inside. Without the protection from the membrane, the bacteria has no defense against the drug and ultimately dies. Principle investigator James Collins remarks, “It’s not so much a silver bullet; more a silver spoon to help the Gram-negative bacteria take their medicine.”
There is an ever-growing list of bacteria that does not respond to medication due to abuse of antibiotics. Most notably, antibiotics are given to livestock, patients take antibiotics until they feel better and do not finish the cycle, and then excess antibiotics are disposed of incorrectly, potentially contaminating groundwater. This has resulted in “superbugs” that are resistant to the effects of antibiotics. As a result, the number of deaths from infections are continuing to grow every year all over the world. Researchers hope that this treatment technique will be a step forward in combating those bacteria, saving hundreds of thousands of lives each year worldwide.
However, before the silver gets released for oral use in humans, a very pressing matter needs to be addressed: toxicity. In large quantities, silver can cause skin to permanently turn a blue-grey color in a condition known as argyria. Additionally, it can be toxic to otherwise healthy tissue. In spite of these concerns, the prospect of using silver ions with antibiotics is still quite promising. Future research seeks to find out which properties of silver are producing the benefit in order to find an alternative substance with similar antimicrobial which could be used in its place without any toxic side effects.