Australian Scientists May Have Just Saved Us From Antibiotic-Resistant Superbugs

Using "star-shaped polymers" the researchers were able to kill bacteria that had become resistance to antibiotics.

by Vincent Dwyer
13 September 2016, 3:17am

Traditional antibiotics. Image via Oliver Dodd/Flickr

"A post-antibiotic era means, in effect, an end to modern medicine," warned the World Health Organisation's director-general Margaret Chan in 2012. As she explained, "Things as common as strep throat or a child's scratched knee could once again kill."

The reasons for this are twofold. Firstly, there are a limited number of known antibiotics. Although more than 150 different types have been discovered since Alexander Fleming stumbled across penicillin in 1928, only one, teixobactin, has been created in the past 30 years.

The other issue is that bacteria are evolving faster than we can create new antibiotics. They develop mechanisms to survive current antibiotics for everything from tuberculosis to UTIs. Subsequently illnesses that should be easy to fix are getting harder to treat, while the threat of antibiotic-resistant superbugs is on the rise.

But a team from the University of Melbourne School may have found another way to kill bacteria. VICE called up the study's lead researcher, Shu Lam, to find out what that is and whether her team just saved us all.

VICE: Hey Shu, can you start by telling me what you've created?
Shu Lam: We've developed a new class of antimicrobial agents, which are very unique. They come in the form of tiny star-shaped molecules that are made from short chains of proteins. We found that they are very effective at wiping out [bacterial] infections in mice and they are also relatively non-toxic to the body.

And how do you kill bacteria with star-shaped molecules?
One of the ways is that the molecule sticks into the surface of the bacteria and rips apart the bacterial cell wall. Once their membrane is destroyed the bacteria dies.

So you're basically jabbing bacteria with molecular ninja stars?
Sort of. These star polymers screw up the way bacteria survives. Bacteria need to divide and grow but when our star is attached to the membrane it interferes with these processes. This puts a lot of stress on the bacteria and it initiates a process to kill itself from stress.

A diagram showing how the star-shaped polymers rip apart the cell wall. Image supplied by the University of Melbourne

How do you build these tiny stars?
For our star molecule, each arm is actually a chain of protein units, and each of these arms are referred to as a polymer. Each polymer is connected at the core. They consist of small chains of proteins, which are essentially called peptides, this is why we call them "peptide polymers." We make them through a method calledpolymerisation. It's basically like playing with Lego... you have small building blocks which you assemble together, you link all of the protein units together to make a long chain, and this chain is called a polymer.

What led your team to start researching these star-shaped polymers?
The expertise in our lab lies in chemistry, and we know chemistry can make cool and useful materials. So we've been working on using polymers to solve problems in healthcare. We have always wanted to develop something that would be useful in overcoming bacterial infections.

Could peptide polymers be used to fight any other diseases or infections?
Currently we are [only] looking at bacterial infections. Our results have shown that we can kill one group of bacteria, but there are many different kinds of bacteria. So we are looking at whether we can expand our system and look at killing all kinds of bacteria.

If more research proves successful, how long until doctors are able to prescribe this sort of medication?
This is quite difficult to answer. We are still quite far from there because we still need to do a lot of studies and a lot of tests—for example, to see whether these polymers have any side effects on our bodies. We need a lot of detailed assessments like that, [but] it they could hopefully be implemented in the near future.

So if this star polymer treatment was available in the future, what would it look like?
The quickest way to make this available to the public is through topical application, simply because you go through less procedures as opposed to ingesting these molecules into the body. So when you have a wound or a bacterial infection on the wound then you [generally] apply some sort of antibacterial cream.

The star polymers could potentially become one of the anti-bacterial ingredients in this cream. Ultimately, we hope that what we're discovering here could replace antibiotics. In other words, we also hope that we will be able to inject this into the body to treat serious infections, or even to disperse it in the form of a pill which patients can take, just like somebody would take an antibiotic.

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