'Predatory Bacteria' May Be Our Best Hope Against Antibiotic Resistance
Military scientists are looking at aggressive bacteria that use grappling hooks and pack hunting to kill other bacteria.
Everything in nature has a predator.
Humans reached the top of the food chain not because of speed, big claws, or sharp teeth, but because our brains developed — along with things like opposable thumbs — to allow us to use tools.
Whether spears to hunt or scalpels to heal, humans have developed numerous tools to keep our species thriving.
But one of them — the discovery and development of antibiotics — is slowly losing its effectiveness.
Antibiotic-resistant bacteria cause 23,000 deaths annually in the United States, according to the Centers for Disease Control and Prevention (CDC).
All told, somewhere around 2 million Americans are infected ever year with bacteria that have built up defenses against the strongest antibiotics currently available.
While antibiotic development slowed because it’s not profitable for pharmaceutical companies, researchers across the globe are investigating new ways to combat drug-resistant bacteria, including viruses and other bacteria that can take them out.
So, some U.S. military-funded researchers have decided to try to use good bacteria to fight really bad bacteria.
Essentially, they’re pitting predator versus predator.
In doing so, they’ve been able to find predatory bacteria that can kill microscopic bad guys with methods straight out of a comic book: grappling hooks, vampiric sucking, and hunting like packs of wolves.
Recruiting ‘good guys’
It’s known as the Pathogen Predators program.
While predatory bacteria grown in military-funded laboratories might sound like the plot to the latest Hollywood pandemic blockbuster, it’s much less cinematic to the naked eye.
It’s simply the latest in a line of alternative strategies to combat an epidemic that has national security concerns.
It’s also of concern to the Department of Defense because soldiers returning from serving overseas come home with infections that can’t be treated, possibly losing a limb or their lives to nearly invisible combatants.
Brad Ringeisen is the deputy director of Biological Technologies Office at the Defense Advanced Research Projects Agency (DARPA), the Department of Defense’s technology research arm.
He said some of their funding for the past four years has been directed at “recruiting the good guys to fight the bad guys” because antibiotic resistance is “a growing threat across the world.”
In animal studies, researchers have been testing these good guys against strains of bacteria that cause infections such as pneumonia and the plague. These diseases could be used as weapons and are resistant to even broad-spectrum antibiotics.
Researchers found that some of the bacteria could kill as many as 145 out of 170 different kinds of bacteria. More importantly, they found the predatory bacteria don’t take over or grow out of control.
“They actually only prey and produce when an infection is present,” Ringeisen told Healthline.
Bdellovibrio to the rescue
The most promising one is Bdellovibrio, which looks like a corn dog with a flexible tail.
It feasts on gram-negative bacteria, which is a particular challenge in the medical and infectious disease field because their membranes protect them from typical antibiotics. Bdellovibrio is gram-negative itself.
It’s a particularly fast predator and once it chooses its prey, it whips out its grappling hooks, pulls it in, burrows inside, and then bursts open, spreading out its daughters, who will also, in turn, go off to hunt more gram-negative bacteria.
Other types of bacteria hunt in groups or suck out its prey’s inside like a vampire, all of which Ringeisen called “fascinating.”
And because these predatory bacteria don’t function like antibiotics, researchers believe that offending bacteria can’t develop defenses around their attacks.
So far, DARPA-funded labs have tested these types of predatory bacteria in the lungs of rats, the brain of a zebrafish, the skin of a pig, and the eye of a rabbit.
More testing needed
There’s still plenty of testing to be done, but this phase of DARPA funding is coming to an end.
Still, DARPA money has gone to researchers at Rutgers University to help find ways to turn these kill-for-good bacteria into usable therapies, whether on a battle field, in response to a terrorist attack, or simply for civilians caught in a current infectious disease epidemic.
DARPA, Reingeisen says, will continue to look at antibiotic resistance in the future, including attempting to link their scientists to clinical research.
We are, after all, trying to win a continuous war against microscopic superbugs.
In an attempt to learn from past mistakes, this includes not merely developing a new antibiotic for bacteria to eventually outsmart. It may soon involve bacteria equipped with grappling hooks.
“I think there are going to be a lot of tools in the toolbox,” Ringeisen said.