By Faye Flam
It’s frustrating enough when progress in medicine plods along slowly, but downright alarming when it starts to backslide. Bacterial infections were considered essentially conquered in the 20th century, and now resistant strains are projected to kill more people than cancer by 2050.
While some people dispute the projected death rate, it’s agreed that bacteria are evolving resistance to antibiotics faster than the drug pipeline can produce new ones. But in the battle between mankind and microbes, some scientists are finding new, more precise strategies for adding to our antibiotic arsenal. Others are finding ways to slow the relentless evolution of resistant bacteria.
Bacteria can evolve with ferocious speed using tricks to increase their genetic diversity, and some can communicate and cooperate. Evolutionary biologists who work on the resistance problem say it will take more to hold them back than simply avoiding unnecessary or inappropriate prescriptions.
In an opinion piece published last December in the journal PLOS Biology, evolutionary biologist Sam Brown of Georgia Tech University advocated a hard push to find alternative ways to treat the most common bacterial ailments — urinary tract and bronchial infections and strep throat. Scientists are already scrambling to come up with alternative ways to treat the sorts of life-threatening infections people get in hospitals, he said, but a better long-term strategy for saving lives would be to focus on preventing the evolution of resistant bacteria in the first place.
The ability to keep the immune system in high gear might come out of the sort of precision work being done at the European Molecular Biology Laboratory. There, biologist Nassos Typas and colleagues pitted a few strains of multi-drug-resistant bacteria against 3,000 combinations — antibiotics paired with each other, or with other drugs or food additives.
The findings, published July 4 in the journal Nature, included a few surprisingly powerful combinations, including an outdated antibiotic called spectinomycin – developed to treat gonorrhea – combined with the food additive vanillin. The vanillin worked very narrowly, enhancing just one antibiotic’s effect on one strain of E. coli.
Most of the 500 combinations that showed some mutually enhancing effect worked narrowly, said Typas. Many of the drugs that boosted the antibiotic effectiveness against one strain detracted from it against others. That’s potentially a good thing, he said, because it could help target the disease-causing bacteria while avoiding collateral damage to our friendly bacteria – what’s become known as the microbiome.
The billions of bacteria that make up your microbiome help you digest food and perform other tasks, and studies show that antibiotics can disrupt them for at least a year. A successful course of antibiotics will build up genes that confer resistance in your microbiome. And the microbiome can transfer these genes to dangerous, disease-causing bacteria.
That’s why Typas said he was so encouraged that some of those combinations had a powerful killing effect on one strain of bacteria but very little effect against others. That would add to mankind’s arsenal without giving away anything to the microbes.
Faye Flam is a Bloomberg Opinion columnist.