Silver: Bad for Bacteria, Not Just Vampires
In medicine, it seems like we’re always looking for a silver bullet — the treatment to end all treatments, the thing that will provide definitive care for patients struggling with infections, diseases and other health problems. While real silver bullets in medicine don’t exist, because no treatment can be 100% reliable, researchers have found something pretty close, and it’s literally made out of silver. It’s also quite ancient, a treatment with a history dating back to Ancient Greece and Rome.
Bacterial infections are notoriously tough to treat, because there are so many bacterial species and they all work in different ways in the body. That goes double for so-called Gram-negative bacteria, which have a doubled cell membrane, making it hard for antibiotic medications to penetrate them and do their work. Scientists have been developing and experimenting with an array of antibiotic medications for decades, and they’re constantly forced to keep researching because bacteria keep evolving to foil their efforts.
Which is why researchers got curious about silver, a metal historically used in the treatment of bacterial infections. While they were aware that the metal seemed to have some antimicrobial effects, they wanted to learn more about how it worked, and about the potential limitations — the problem with silver is that if patients receive too high a dose, they can start experiencing complications, including a condition that permanently discolors their skin. What they found is that while silver alone may not be enough to kill off an infection, when silver and antibiotics are teamed up, they can sometimes lick a tough infection.
Here’s how it works: antibiotics function by producing toxins that lead to cell death, but in order to be effective, they have to be able to penetrate the cell first. Silver bonds to sulfur, an important component of proteins, and makes it impossible for those proteins to fold correctly, so they can’t do what they’re supposed to do, like, say, creating a cell membrane. Consequently, the silver creates openings for the antibiotics to get inside and start interfering with the function of bacterial cells.
It does more than that, though. It interferes with the way bacteria use iron, a critical metal, and it also forces bacterial cells to start producing reactive oxygen species, which damage the cell. Imagine firing a bullet inside a crowded room: that’s what silver does to bacteria, ricocheting around to create chaos. The fact that it makes cells more susceptible to antibiotics allows doctors to use less, which reduces the risk of side effects for the patients. It also reduces antibiotic resistance, making formerly resistant infections vulnerable to treatment again.
Thanks to the one-two punch, the patient doesn’t need to take high doses of silver or antibiotics, and thus runs a much lower risk of side effects. And her infection is more likely to respond quickly, with the antibiotics capable of killing tens to thousands more bacteria than they would on their own.
This approach to treatment still needs some more research before it can be rolled out on a large scale, to make sure it’s safe and effective, but this is a good start in an often frustrating area of research. As the world’s population grows and antibiotic use increases, more and more antibiotic-resistant infections are arising, and they’re spreading like wildfire through hospitals and other health care facilities. The more tools we have in our arsenal, the better, especially for immunocompromised patients who aren’t able to fight such infections effectively on their own, and thus are at a higher risk of death and severe complications.
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