WHY THIS MATTERS IN BRIEF
- Bacteria’s stellar ability to rapidly evolve to overcome today’s most potent antibiotics puts tens of millions of lives at high risk, but now scientists are designing new genetics based antibiotic treatments that could kill off bacteria’s natural advantage
Even since Alexander Fleming stumbled across penicillin, the first antibiotic drug, scientists knew that our fight with evolution had just begun – they also knew that one day these then advanced medicines would become obsolete. And as anti-biotic resistance increases, as the World Health Organisation (WHO) lists anti-biotic resistance as one of the greatest threats to humanity, capable of increasing the number of deaths around the world by tens of millions of people per year, that day is approaching. Fast.
Most antibiotics work by blocking the biological processes that allow bacteria to thrive and multiply, but with prolonged, low dosage use, antibiotics become a source of stress that prompts the bacteria’s evolutionary DNA machinery to kick in to create new anti-biotic resistant strains, and when one of them becomes resistant they all do.
In one of the most chilling demonstrations you can see this in action in the video below where a single strain of bacteria takes just eleven days to become impervious to doses of anti-biotics that are 1,000 times more powerful than were needed to kill the original bacterial strain.
Even worse though, and if all this wasn’t bad enough already, because the same family of anti-biotics generally work on the same biological pathways, when one bacterium evolves a mutation that resists one type of drug, it often renders that entire family of drugs useless.
It’s this arms race that is forcing scientists to think differently.
Now teams of scientists have found a new approach to tackle anti-biotic resistance – a “CRISPR pill” that instructs harmful bacteria to shred their own genes to bits. In short it’s a genetic chainsaw, like the ones I’ve covered before.
In essence, scientists are returning CRISPR, the world’s most powerful real time gene editing tools, to its roots, and while CRISPR’s best known as a handy way to manipulate DNA in anything and everything it turns out that the CRISPR mechanism is actually a part of the bacteria’s natural immune defence system. And just like our immune systems that can turn against themselves, scientists are now hoping to give harmful bacteria a destructive auto-immune disease.
When it’s finished this CRISPR pill, this chainsaw in a capsule, will have the ability, unlike today’s “kill ‘em all” anti-biotics, to precisely target single strains of harmful bacteria, and leave other types, such as the beneficial bacteria in the gut, intact.
This truly is a case of smarter, not stronger.
“The downside of antibiotics is they are a sledgehammer that depletes and destroys the gut microbial community,” says Dr. Jan Peter van Pijkeren at the University of Wisconsin Madison, who is working on CRISPR based antibiotics, “you want to instead use a scalpel in order to specifically eradicate the microbe of interest.”
“The idea of CRISPR based approaches is to enact sequence-specific antimicrobial activity, placing selective pressure against genes that are bad rather than conserved bacterial targets,” explains Dr. Timothy Lu at MIT who’s leading his own team, “the way I view it is not that we will be able to make an evolution proof therapy, but that the genetic engineering tools will become more robust so that as evolution happens, we can rapidly develop countermeasures.”
