Melbourne scientists make breakthrough against antibiotic resistant superbugs

A scientist looks at a bacteria culture - image courtesy of DFC. Antibiotic resistant bacteria are a significant concern for human-beings.

Melbourne scientists have made a major breakthrough in combating antibiotic resistant superbugs which threaten to be one of the greatest risks to human health in the 21st century.

The research team from the University of Melbourne’s School of Engineering made the discovery as part of work to find treatments for cancer. The breakthrough could help defeat antibiotic resistant superbugs, which have been identified by the World Health Organisation as one of the greatest threats to human health after adapting to become resistant to all forms of antibiotics.

These forms of antibiotic resistant bacteria threaten to kill millions of people a year, according to Britain’s Treasury.

PHD candidate and member of the Melbourne research team, Shu Lam, has had her research published in the prestigious Nature Microbiology journal.

The research shows that a class of antimicrobial agents, which the Melbourne team calls ‘structurally nano engineered antimicrobial peptide polymers (SNAPP), exhibit sub-μM activity against all Gram-negative bacteria tested, including ESKAPE and colistin-resistant and MDR (CMDR) pathogens, while demonstrating low toxicity.

The report showed that comprehensive analyses revealed that the antimicrobial activity of SNAPP’s proceeds via: ‘a multi-modal mechanism of bacterial cell death by outer membrane destabilization, unregulated ion movement across the cytoplasmic membrane and induction of the apoptotic-like death pathway’, which the research team stated possibly accounted for why they did not observe resistance to SNAPPs in CMDR bacteria.

Protein molecules ‘rip apart’ antibiotic resistant bacteria

In conjunction with these findings published in the Nature journal, Lam said the Melbourne research team had created a chain of star-shaped protein molecules called peptide polymers that could defeat the superbugs by “ripping apart” their cell walls.

A bacteria cell (L) and after (R) treatment with star-shaped peptide polymers - image courtesy of Melbourne University
A bacteria cell (L) and after (R) treatment with star-shaped peptide polymers – image courtesy of Melbourne University.

Lam and her team said that, unlike antibiotics, the superbugs showed no signs of resistance to the molecules and, that by “ripping apart” their cell walls, would make it very difficult for these bacteria to adapt and to survive after being treated by the peptide polymers.

To help find the molecules which could breakthrough the superbugs antibiotic barriers, Lam and her team tested six different superbugs in vitro i.e: outside a living body. They found that the star-shaped peptide polymer killed the bacteria and did not damage the red-blood cells in the in vitro environment.

The Melbourne team also tested the efficacy of the polymer in vivo, inside mice, against one type of superbug bacteria, and found that the peptide polymers were effective in the treatment of this specific bacteria.

Lam said the team’s work was still in the very early stages and had so far focused on one major class of bacteria. She said more research was needed to examine how other types of bacteria responded to the protein molecules.