In 1945, Alexander Fleming used his Nobel Prize lecture to warn that misuse of antibiotics would one day render them useless.

Eighty years later, that warning has arrived.

Drug-resistant bacterial infections killed an estimated 1.14 million people globally in 2021, with projections reaching 1.91 million annual deaths by 2050.

A new review published in Microorganisms points to an unexpected ally: silver.

Specifically, silver nanoparticles—tiny particles that slowly release silver ions—appear to restore the power of antibiotics that have stopped working on their own.

Why Scientists Are Revisiting Silver Nanoparticles

Silver’s antimicrobial properties are not new. Ancient Greeks stored water and wine in silver vessels.

By 1897, a colloidal silver product called Collargol was sold for medical use, and silver-based treatments like Argyrol and Protargol remained popular over-the-counter remedies for syphilis and bacterial infections for fifty years.

Silver fell out of favor when penicillin arrived in the 1940s, but with antibiotics now failing, researchers are taking another look.

The mechanism is multilayered.

Silver ions rupture bacterial cell membranes, generate damaging reactive oxygen species, interfere with DNA replication, and shut down energy production.

As the authors describe it, these effects “weaken bacterial metabolism and overwhelm bacterial defenses,” leaving the microbes vulnerable to antibiotic attack.

The laboratory results are remarkable. One study found that combining silver nanoparticles with antibiotics produced up to a 31-fold increase in antimicrobial activity.

Another showed silver nanoparticles paired with the antibiotic amikacin were ten times more effective than amikacin alone against drug-resistant biofilms—the stubborn bacterial communities that form on medical implants and chronic wounds.

Silver has even restored sensitivity in bacteria that are fully resistant to colistin, a last-resort antibiotic, by directly inhibiting the resistance enzyme.

Silver’s Future in Modern Medicine

Notably, silver appears safe for human cells at the concentrations needed to kill bacteria. Mammalian cells tolerate silver ions far better than microbes do, and concentrations below 10 µg/mL are generally considered safe for human tissue.

Applications are already advancing in wound dressings, catheter coatings, and implant surfaces designed to prevent infection before it begins.

In an era when each new antibiotic buys only a few years before resistance catches up, silver may offer something rare: a way to make the drugs we already have work again.

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Adapted from: Casals E, et al. “Silver Nanoparticles and Antibiotics: A Promising Synergistic Approach to Multidrug-Resistant Infections.” Microorganisms. 2025;13(4):952. doi:10.3390/microorganisms13040952