We finally have hope for stalling the victory march of antibiotic-resistant superbugs, thanks to the latest breakthrough in the search for new antibacterial agents.
Australian researchers, led by University of Melbourne PhD candidate Shu Lam and her supervisor, Professor Greg Qiao, have engineered a synthetic antibacterial protein they hope could one day be used as an alternative to antibiotics. The study was published today in Nature Microbiology.
“There haven’t been many new antibiotics discovered in the last 30 years, or even 50 years, so it’s important to have alternatives to help in controlling bacteria and infections,” Qiao, an expert in polymer and biomolecular chemistry, tells SBS Science.
Mimicking from nature
Looking for new ways to kill bacteria, Qiao’s team analysed and mimicked the structure of antimicrobial proteins (AMPs), a group of small proteins that play a key role in the immune systems of many animals. Thus they were able to create a bacteria-killing protein they classed as a ‘star-shaped peptide polymer’.
The researchers have demonstrated this polymer is able to eat through the thick, protective membrane of a bacterium, causing it to die. This makes it extremely effective in killing Gram-negative bacteria.
Members of this major class of bacteria, which includes E. coli, salmonella and legionella, are highly prone to developing resistance to antibiotics by rapidly mutating.
Qiao explains that a key benefit of the new antibacterial polymer is that it is significantly less toxic to human cells than AMPs and some antibiotics.
“We’re talking about 100 times difference in terms of the toxicity,” he says.
The other major advantage it has over AMPs and antibiotics is that in laboratory tests it was still highly effective at killing superbugs even after they had mutated multiple times – this is the point at which most antibiotics become useless.
A 'very promising' step forward
Currently, the only treatments we have for bacterial infections are antibiotics, but the rise of antibiotic resistance means there is now a sense of urgency in the quest for alternative drugs.
The first instances of antibiotic resistance developed only a few short years after the introduction of penicillin, but only over the past decade it’s become a major global health concern, expected to cause up to 10 million deaths per year by 2050.
Earlier this year, scientists unveiled Teixobactin, which was the first new antibiotic to be discovered in almost 30 years.
Associate Professor Anthony George, an expert in multidrug resistance and pathogenic bacteria from the University of Technology, Sydney, says the findings of the new study are “very promising”.
“The best thing about this is that it’s sort of like an indirect mechanism of disruption, and therefore it would be harder for the bacteria to develop resistance and take much longer if they can develop resistance,” he tells SBS Science.
“Whether resistance develops in time or other problems develop, it’s hard to say until we actually go into the trial period, but it looks very promising.”
The next step in the research will be to conduct clinical trials to determine the dosage, toxicity profile and efficacy of the peptide polymer, but George is confident that it will have a major impact if it is cleared for human use.
“If they work, the chances are that for quite a few years into the future, you’re going to see a much, much better response of patients, in hospitals especially, and a much lower death rate and much lower rate of infection.”
Editor's note: This article was updated on 19-09-2016 to reflect PhD student Shu Lam's leading role in this research.