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Fighting superbugs with lasers

Antibiotics are becoming less effective due to antimicrobial resistance (AMR) – so lasers are being used instead.

Why use lasers to kill bad bacteria?

Antibiotics are used widely to kill bad bacteria. However, many of the microbes responsible for human diseases are now resistant to a number of antibiotics – such microbes are often called “superbugs”. Antimicrobial resistance (AMR) is a threat across all of medicine and undermines treatments that doctors, their patients and the public have come to rely on. As drug resistance spreads, common infections and injuries that were once easily treatable become harder, and in some cases impossible, to treat. It is therefore essential that alternatives to antibiotics are developed so that we can prevent and treat infections due to these superbugs.

From research...

At UCL, we have been carrying out research over a number of years, and in a number of different areas, to try and find solutions to the problem of AMR. One such solution involves bypassing the drugs entirely and using a new way to eliminate harmful bacteria – with lasers. This technique uses a special chemical (known as a light-activated antimicrobial agent – LAAA) that can be activated by red light to make it lethal to all types of microbes, including superbugs. The technical name for this approach is antimicrobial photodynamic therapy (aPDT), and our research has shown that microbes cannot develop resistance to this treatment.

...to reality

It is one thing to show that this procedure works in the laboratory, but quite another to show that it is safe and effective to be used on patients, and the road from research to reality can be long. In this case, realising the benefits of aPDT has taken over three decades of work, including the publication of 84 journal articles, contributions to 34 conferences and over ten patents. However, aPDT is now being used to treat periodontitis (gum disease – the main cause of tooth loss in adults) in many countries. It is also being used to kill MRSA – methicillin-resistant Staphylococcus aureus, one of the most notorious super-bugs – in the noses of patients before they have surgery. MRSA in the nose can infect surgical wounds, and several hospital studies have shown that aPDT of the nostrils considerably reduces the risk of such post-surgical infections. Having licensed the patent to Ondine Biomedical Inc., a Canadian company, the treatment, commercially known as Steriwave, is now available to UK patients through the NHS.

But there is more to do

While the development of aPDT is good news, it has taken several decades for the research to become a reality for the patients it now protects. This therapy provides one weapon in the war against AMR, but unfortuantely there are many more battles that need to be won, and the AMR clock is still ticking. If antibiotics lose their effectiveness, key medical procedures (such as gut surgery, caesarean sections, joint replacements, and treatments that depress the immune system, such as chemotherapy for cancer) could become too dangerous to perform. In 2016, the O'Neill Report (The Review on Antimicrobial Resistance) estimated that by 2050, ten million lives per year will be at risk due to the rise of drug resistant infections if proactive solutions to slow the rise of AMR are not found now. Further research is needed to find and develop new therapies in order to protect patients now and into the future.