Fighting antibiotic resistance with antimicrobial RAFT polymers

The challenge

Increased antimicrobial resistance is challenging global public health

As bacteria become more resistant to commonly used antibiotics it is becoming increasingly difficult to treat a range of infectious diseases using existing antibacterial drugs.

There is a need to develop a whole new generation of antibiotics that can overcome bacterial resistance, and to find new ways of administering treatments that target specific sites of infection, leaving the bacteria less time and opportunity for resistance.

Naturally produced 'host defence peptides' that help some plants and animals fight off infection, is one solution to this challenge. These naturally occurring antimicrobial peptides (AMPs) form an integral part of an organism's host defence system. Many of these peptides have been shown to possess broad‐spectrum antimicrobial activity and a low susceptibility to the development of microbe resistance.

However, the human body is designed to break down peptides, so keeping this naturally occurring 'medicine of Mother Nature' intact for long enough to be effective poses a further challenge. These therapeutic agents can also be costly to produce at scale.

Our response

Mimicking nature - finding new ways of administering infection-fighting drugs

Our RAFT team has been developing ways to mimic the protective peptides using polymers – a synthetic material that is not so easily broken down. In a world first we have demonstrated through extensive studies that our RAFT polymers can eradicate single and mixed microbial biofilm infection, which has been identified as the likeliest cause of delayed healing in chronic, open wounds. A biofilm occurs when microbes stick to each other on a surface and form a protective layer around their community. This protective layer means that commonly used antibiotics are no longer able to get to the bacteria to kill them and are rendered useless. Our polymers are able to effectively breakdown these biofilms, far outperforming any clinical combination tested.

Our Antimicrobial Polymer Technology (provisional patent) has turned out to be highly effective, demonstrating activity against pathogenic bacteria and fungi, and even some antibiotic-resistant strains of bacteria. The technology is cheaper than peptides and easier to produce on a large scale. It provides more options for chemical manipulation, and has low human cell toxicity and low susceptibility to microbe resistance.

The results

Optimal candidates identified

Activity has been observed against various bacteria and fungi including S. aureus, S. epidermidis, E. coli, K. pneumoniae and C. albicans, with very low doses being effective enough to destroy the pathogens. We have also seen that this activity is maintained against resistant strains such as against vancomycin and methicillin dual-resistant S. aureus. This technology is also not toxic towards human cells with haemocompatibility studies using human red blood cells and cytotoxicity assays using mammalian cells showing that polymers display minimal toxicity within therapeutic concentrations.

With 'host defence peptides' protecting their hosts from the threat of invading bacteria for millions of years now, and bacteria still showing little sign of developing resistance to them, it makes perfect sense that we should look back to Mother Nature and learn our lessons from her on this one.

Potential Applications for Antimicrobial Polymer Technology

Artificial polymer-infused materials in the form of wound dressings and catheter coatings may be the answer to treating infections that are currently threatened by antibiotic resistant bacteria. Potential applications include:

• treatment of chronic wounds (e.g. wound dressings for MRSA infections)
• treatment of eye infections (e.g. candidiasis of the eye)
• treatment of resistant infections (e.g. biofilm based infections, patent filed)
• antimicrobial contact lens solutions
• development of antimicrobial coatings for medical devices
• catheter lock solutions (removal of biofilm growth from surfaces).

The team is seeking partners to take this technology forward to the clinic. Do business with Manufacturing.