Could Silver Help Save The Human Race?
Silver has been used to fight infection for thousands of years. Hippocrates first described its antimicrobial properties in 400 BC.
And this year, a team led by James Collins, a biomedical engineer at Boston University in Massachusetts, has described how silver disrupts bacteria, and demonstrates that the ancient treatment could help to deal with the thoroughly modern scourge of antibiotic resistance. The work is published today in Science Translational Medicine1.
“Resistance is growing, while the number of new antibiotics in development is dropping,” says Collins. “We wanted to find a way to make what we have work better.”
According to Collins and his team, silver – in the form of dissolved ions – attacks bacterial cells in two main ways. First, it ensures the cell membrane is more permeable, and it interferes with the cell’s metabolism, leading to the overproduction of reactive, and usually toxic, oxygen compounds.
Both mechanisms could be harnessed to make today’s antibiotics more effective against resistant bacteria.
Many antibiotics kill their targets by producing reactive oxygen compounds, and Collins and his team demonstrated that when boosted with a small amount of silver these drugs could kill between 10 and 1,000 times as many bacteria.
The increased membrane permeability also enables more antibiotics to enter the bacterial cells, which may overwhelm the resistance mechanisms that rely on shuttling the drug out.
“It’s not so much a silver bullet; more a silver spoon to help the Gram-negative bacteria take their medicine,” says Collins.