A novel technique could decrease resistance to antibiotics with a bacteria-killing bioactive glass that reduces infections.
Scientists at Aston University have discovered a new method that significantly increases the antimicrobial properties of a material utilised in many medical devices such as catheters and clinical surfaces – bioactive glass. Thus, reducing the prevalence of bacterial infections and subsequently, mitigating the increasing rate of resistance to antibiotics.
Resistance to antibiotics is a significant burden to the global healthcare system; many bacteria that cause infections such as Escherichia coli and Staphylococcus aureus, is becoming increasingly resistant to treatment. Therefore, the requirement for new methods to prevent infections is urgently needed.
Mitigating resistance to antibiotics
The Aston University team had already developed bacteria-killing bioactive glass laced with a single metal oxide of either zinc, cobalt, or copper. However, their latest research combined pairs of metal oxides in the material, and they discovered that some combinations were more than 100 times better at killing bacteria than single oxides alone.
Bioactive glass is made from high-purity chemicals designed to induce specific biological activity, but the type currently in clinical use – often as a bone filler – does not contain antimicrobial substances. The research showed that combinations of metal oxides can improve the antimicrobial properties of bioactive glass and the researchers believed this approach could be applied to other materials for clinical use.
Thus, this discovery would consequently decrease bacterial infections by increasing the antimicrobial properties of the glass, and resistance to antibiotics would reduce as there would be no need to prescribe them.
Professor Richard Martin, who led the research at Aston University’s Engineering for Health Research Group, said: “Antibiotic drugs have been used in combination since the 1950s, as two antimicrobials can broaden the spectrum of coverage by aiming for different bacterial targets at the same time. Our research is the first to show that this combination approach can work with materials as well.”
Analysing the bacterial properties of bioactive glass
Professor Martin and his colleagues, Drs Tony Worthington and Farah Raja, created bioactive glass laced with small amounts of cobalt, copper or zinc, and combinations of two of the three oxides.
Then, they grounded these into a powder which they sterilised, before adding it to colonies of E. coli, S. aureus and a fungus, Candida albicans. They compared the effects of the standard glass and glass with either solo metal oxides or the combinations, measuring bacterial and fungal kill rates over 24 hours.
All of the metal oxide-laced glass – both single and combined – performed better than the glass alone. The researchers discovered that copper, combined with either cobalt or zinc, had the strongest effect on bacteria, followed closely by a combination of cobalt and zinc.
Both copper combinations were over one hundred times better than single oxides at killing E. coli, whilst copper and zinc were similarly effective against S. aureus. They also discovered that the cobalt and zinc combination had the strongest effect on the fungus.
This could be a key breakthrough in alleviating resistance to antibiotics by utilising bioactive glass in medical devices and clinical surfaces.
Professor Martin said: “It was exciting to run our experiments and find something that is significantly better at stopping infection in its tracks and could potentially reduce the number of antibiotic treatments that are prescribed. We believe combining antimicrobial metal oxides has significant potential for numerous applications including implant materials, hospital surfaces and wound healing dressings.”
Dr Worthington concluded: “We have shown that co-doping surfaces with these combined antimicrobial metals, including copper, zinc and cobalt, could reduce bacterial adhesion and colonisation to surfaces or devices used in clinical practice.
“The use of antimicrobial metals is potentially the way forward, given discovery of new antibiotics is currently limited. We would urge manufacturers to investigate whether our new approach could be used for their biomedical materials.”
