evidence: Like werewolves and vampires, bacteria have a weakness: silver. The precious metal has been used to fight infection for thousands of years — Hippocrates first described its antimicrobial properties in 400 bc — but how it works has been a mystery. Now, a team led by James Collins, a biomedical engineer at Boston University in Massachusetts, has described how silver can disrupt bacteria, and shown that the ancient treatment could help to deal with the thoroughly modern scourge of antibiotic resistance. The work is published today in Science Translational Medicine. [...] Collins and his team found that silver — in the form of dissolved ions — attacks bacterial cells in two main ways: it makes the cell membrane more permeable, and it interferes with the cell’s metabolism, leading to the overproduction of reactive, and often toxic, oxygen compounds. Both mechanisms could potentially be harnessed to make today’s antibiotics more effective against resistant bacteria, Collins says. [...] Before adding silver to antibiotics, "we’ll have to address the toxicity very carefully", says Fowler. Ingesting too much silver can also cause argyria, a condition in which the skin turns a blue-grey color — and the effect is permanent.