When a 43-year-old Chicago woman caught a sinus infection in 2009, she never imagined it could kill her. But five years later, after multiple antibiotics had failed to work, her body began to shut down: She could barely eat, her vision suffered, her head spun, and her joints ached. She had contracted methicillin-resistant Staphylococcus aureus (MRSA), one of about 20 multidrug-resistant superbugs that together infect about two million people in the United States every year, killing 23,000 of them.

Desperate, the woman turned to the internet, where she discovered a treatment called phage therapy, an alternative to antibiotics that is not currently approved by the Food and Drug Administration but is attracting excitement as our national stockpile of antibiotics grows increasingly less potent. In July of last year, the world's first scientific trial of the therapy began in Europe. In January, the National Institutes of Health dedicated funds to studying it here. And this month, a startup called AmpliPhi Biosciences, in partnership with the U.S. Army, released the results of the first major FDA study of the treatment's safety.

Bacteriophages (literally, "bacteria eaters") are scary looking, but they infect bacteria instead of humans. They're also everywhere: There are more of them on Earth than all creatures combined. Getty Images

This is a coup for a medical technique that was popular before the discovery of penicillin and which has for years only been available in countries like Russia, Georgia, and Poland. It's a lot like returning to old warplanes from modern fighter jets and realizing that the original planes had certain advantages all along.

The "phage" in phage therapy is short for bacteriophage, which is a type of virus that infects bacteria rather than people. Doctors in Eastern Europe create cocktails of them to give to patients. The woman with the sinus infection flew to a clinic in Tbilisi, Georgia, to receive one of these cocktails for ten days. She has since tested negative for MRSA. Twice.

"Phages are extremely specific for the bacteria we want to kill," says Robert Ramig, a microbiologist at Baylor College of Medicine. Each virus prefers a single species, so doctors can target bad bacteria and spare beneficial strains. In cases where bacteria develop resistance to the phages, doctors just create a new cocktail. Or they can give patients phages and antibiotics at the same time. "For some reason, when bacteria become resistant to phages, they lose their resistance to antibiotics, which often become effective again," says Ramig. "The bacteria lose either way.

The FDA's strict rules about drug safety make it virtually impossible to approve the personalized phage cocktails used in Georgia, which is why AmpliPhi is testing blends for common bacteria. But because bacteriophages are already everywhere (there are roughly 10 million in a drop of ocean water), the FDA's less stringent food-additive arm has already approved phages for food producers to spray on meat. The sprays, which are organic, kill more than 99 percent of the nasty bugs they touch. The post-antibiotic age may be coming, but we're not out of weapons yet.

*This article originally appeared in the October 2016 issue of Popular Mechanics.

This content is created and maintained by a third party, and imported onto this page to help users provide their email addresses. You may be able to find more information about this and similar content at piano.io