With overuse of antibiotics, superbugs continue to evolve

Sabri Ben-Achour Dec 14, 2022
Heard on:
Bottles of antibiotics line a shelf at a Florida pharmacy in August 2007. In the U.S., there are nearly 3 million antibiotic resistant infections each year. Joe Raedle/Getty Images

With overuse of antibiotics, superbugs continue to evolve

Sabri Ben-Achour Dec 14, 2022
Heard on:
Bottles of antibiotics line a shelf at a Florida pharmacy in August 2007. In the U.S., there are nearly 3 million antibiotic resistant infections each year. Joe Raedle/Getty Images

Back in 2014, Tori Kinamon was a freshman in college at Brown University, competing in Division I gymnastics. 

“I was feeling the strongest most physically fit I had ever been and competed in one of our championship competitions,” she said.

A couple of days later, her left leg felt sore. “Doing gymnastics, you get aches and pains now and then so I didn’t think much of it and just tried to train through the pain,” she said. 

But it was no pulled hamstring, and it got worse.

“Honestly, my pain increased exponentially and I started to feel fever chills night sweats, felt sick to my stomach, just very fatigued,” she said. “Eventually I was admitted to the hospital so I was started on IV antibiotics.”

The antibiotics did not work.

An infection spread down Kinamon’s leg. “The pain was honestly unbearable,” she recalled. “And they took me in for emergency surgery and discovered that I had an 18 centimeter MRSA infection that eats away at the muscle.”

MRSA stands for methicillin-resistant Staphylococcus aureus. It’s a bacteria that has developed resistance to many antibiotics. Kinamon asked if her leg would have to be amputated, but doctors “couldn’t answer that question.”

But there was an antibiotic, vancomycin, that still worked for MRSA. They flooded Kinamon’s body with it and operated on her eight times in two weeks. Vancomycin, however, can be toxic to the kidneys, and Kinamon’s kidney function started to precipitously decline.

Kinamon did not, however, have to choose between her kidneys and her leg, because there was another antibiotic left to try — this would be attempt number three. It worked.

“When I was being discharged from the hospital, I was nervous. You know, I kept wondering, ‘How do you know the infection is gone? How do you know it’s not gonna come back?'” she said. “And the recovery did not end when I left the hospital. I have a 2-foot long scar on the back of my leg, and probably had 150 stitches.”

Kinamon remained infection-free and is now a medical student at Duke University with a special interest in antibiotic research. 

“We are already seeing from 2019 data 1.3 million deaths directly attributable across the world to superbugs in that year,” said Dame Sally Davies, a physician and the U.K. government’s special envoy on antimicrobial resistance. 

“Not only is this more frequent than each of HIV, TB and malaria, nearly 5 million people every year have a drug-resistant bug in them or on them when they die,” Davies said — making antimicrobial resistance the third most important underlying cause of death after heart disease and stroke.

In the U.S. alone, there are nearly 3 million antibiotic resistant infections every year that kill 35,000 people. And as time goes on, more bacteria, fungi and other pathogens are developing resistance to the medicines used to kill them. 

The cause of this is fairly straightforward.

“Well, there’s this guy named Darwin,” said Dr. Vance Fowler, a professor of medicine at Duke University.  It’s evolution. “Think about a situation where there’s an individual who has a particular bacterial infection who’s treated with a course of antibiotics that kills the majority of the bacteria, but a tiny portion of them persist.”

Those survivors may have a mutation or might have borrowed genetic material from another bacterial species. They divide in minutes and create a generation of superbugs.

Contrary to a persistent myth, “it is not us, as people, who develop resistance to the drugs,” said Davies.  “It is the bacteria themselves.”

People, however, help them along. Primarily through “the use of medicines, not in the way they are supposed to be used,” said Haileyesus Getahun, a Director of Antimicrobial Resistance at the World Health Organization.

The more often antibiotics are used, the more opportunities bacteria have to evolve. So, for example, people insisting on taking antibiotics for a cold — which is caused by a virus that isn’t affected by antibiotics — is an opportunity for bacteria to develop resistance. 

But 80% of the antibiotics used in some countries are used in the food chain for animals, according to Davies. And some agricultural producers misuse them.

“The use of antibiotics for nonveterinary use, for example, to fatten animals,” Getahun said.

Using antibiotics to fatten animals is banned in the U.S., and major chicken producers like Perdue have all but eliminated the use of antibiotics from their flocks. But some beef producers still use antibiotics that are also used for humans, and that the World Health Organization says should not be used in agriculture

But if health care and agriculture are one losing frontier in the war on superbugs, economics is another.

“We have very few new antibiotics coming in, and it really is to do with a market failure,” Davies said. More on that in the next installment.

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