Credit: CDC
Right now, if you become infected with streptococcal pharyngitis—the bacteria that causes strep throat—it can be easily treated with a trip to the doctors, a wooden stick down your throat, and about 7 days of antibiotics.
In 30 years, however, that may not be the case. In fact, the once relatively harmless streptococcal pharyngitis could end up killing you if it stops responding to treatment with antibiotics. The World Health Organisation (WHO) predicts that in 2050 more people will die from once-common infections than cancer. Antibiotic resistance is a ticking bomb for public health, with thousands upon thousands of scientists researching possible ways to prevent bacteria from killing millions of people per year.
In the past few months alone, scientists have: tried to prevent resistance proteins from forming, employed genetically engineered bacteriophages, created a glowing molecule that can bind to a resistant enzyme, and even developed a synthetic antibiotic that can target deadly superbugs.
Now, a team of researchers from the University of Southern Denmark is taking a different approach by asking a question that may sound counter-intuitive: can more lives be saved if we let resistant bacteria live?
Birgitte Kallipolitis, head of research in the Department of Biochemistry and Molecular Biology, and her team are trying to solve the problem of antibiotic resistance not by killing the offending bacteria but by rendering it benign.
To do this, the research group is focusing on a specific type of fatty acid known as free fatty acids, which are known to exhibit antimicrobial and anti-virulent properties. In a new study published in Frontiers in Microbiology, the team used the foodborne pathogen Listeria monocytogenes to test the effect of the fatty acids.
The experiments confirmed free fatty acids do indeed possess an antimicrobial effect as they were able to kill the bacterium. But, “just” killing the bacteria is not enough—mutations will arise and a new, more resistant version will spawn.
That’s where the properties of the free fatty acids come into play. The study showed not only do they kill the bacteria but they render the resistant bacteria harmless by turning off their ability to infect and spread.
“The resistant bacterium is no longer a bacterium that we must try to kill. Instead, we prevent it from spreading and making us sick,” said Kallipolitis.
Unfortunately, the Listeria in the experiments were only harmless as long as their virulence was switched off. Once they are no longer exposed to the free fatty acids, the bacteria quickly regained the ability to spread.
But, Kallipolitis says that short time period may be all that is needed.
“This may be the extra help that allows a patient to cope with an infection,” the molecular biology professor explained. “Antivirulent medication or supplements could be good for the prevention of infections, especially in the elderly and weak.”
For the study, Kallipolitis and her team exploited the free fatty acid lauric acid, which is naturally found in nuts, seeds, plants and milk. But, as Kallipolitis points out, you cannot eat your way to an anti-virulent effect. In order to protect, the fatty acids must be in the free form—and that does not occur in food. Although that does open the door to the possibility of manipulating food and/or supplements to provide fatty acids in the free form.
“We do not yet know if you can achieve the effect by consuming even free fatty acids,” said Kallipolitis. “Maybe the fatty acids are metabolized before they reach the battle ground in the intestinal system, where the fight against many resistant bacteria takes place. Maybe we need pharmacists or chemists to find a way to transport the fatty acids to the scene of the battle.”
So while a future dietary supplement or tablet is not out of the question, there are more than a few research steps to be taken in the meantime.
Next, Kallipolitis says her team will test the anti-virulence effect of the free fatty acids in a laboratory system reminiscent of the human intestinal system, before turning to mouse experiments. If all goes well, the team hopes to test the approach prophylactically in humans.