A growing threat could kill 10 million people by 2050, but one company thinks it can stop it

Our best line of defense against life-threatening illnesses has turned against us. Antibiotics - which we've relied on for decades to beat deadly, contagious infections - are set to kill 10 million people by 2050.

After years of abuse in people and animals - with doctors practically doling them out like candy and farmers stirring them into animal feed - antibiotics have virtually stopped working. In January, a woman died after a raging infection that failed to respond to 26 different kinds of antibiotics. The bacteria have outsmarted us, and they're stronger than ever.

The problem doesn't end there.

In addition to spurring the creation of more and more powerful infections, antibiotics aren't good for our bodies. Like a carpet bomb, the drugs attack indiscriminately, neutralizing the good bacteria in our guts in addition to the bad ones that make us sick.

A better solution might involve targeting only the infection-causing bacteria, rather than killing everything in our guts and contributing to the growing threat of antibiotic resistance. This is something a new startup called Eligo Bioscience is working toward. On Tuesday, the company secured a $20 million Series A round of financing led by Khosla Ventures and Seventure Partners, including a $2 million award from the Worldwide Innovation Challenge.

"We either have antibiotics, which are like weapons of mass destruction and kill everything, or we have probiotics that are just adding things, mostly to treat the symptoms, not to treat the cause," Eligo founder and CEO Xavier Duportet told Business Insider.

Eligo Bioscience wants to create what it calls "eligobiotics" - smart drugs that enter the gut with precision and destroy only the harmful bacteria, sparing all the microbes that keep our guts happy and healthy.

The drugs, which so far have only been tested in mice, work by taking advantage of a precise new form of gene editing called CRISPR. The smart drug technology would not involve genetic modification - it would use CRISPR to selectively kill harmful bacteria in the gut.

"We use these little nanobots that have essentially been programmed to scan all of your DNA and seek and destroy specific sequences in bacteria," Duportet said.

Once the bots find bits of genetic material that code for harmful bacteria, they activate a kind of microscopic genetic scissors that snip the ribbon of the bacteria's genetic code, rendering it powerless.

"They essentially plug up the gears of the antibiotic resistant bacteria so they can no longer work," Duportet said.

If further trials in mice - eventual clinical studies, currently slated for 2020 - are successful, the drugs would ideally be taken as a pill.

"This is a bit futuristic, but eventually we envision having a pill that will clean your microbiome daily," Duportet said. "It's the ultimate form of personalized medicine."