Blue light might just take the "super" out of superbugs

Blue light might just take the...
Researchers have found that shining blue light on antibiotic-resistant bacteria can make them vulnerable to drugs again
Researchers have found that shining blue light on antibiotic-resistant bacteria can make them vulnerable to drugs again
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Mohamed Seleem, an author of the study
Mohamed Seleem, an author of the study
Researchers have found that shining blue light on antibiotic-resistant bacteria can make them vulnerable to drugs again
Researchers have found that shining blue light on antibiotic-resistant bacteria can make them vulnerable to drugs again

Antibiotics were one of the 20th century's most important scientific discoveries, but their usefulness is quickly fading. Overuse has led to bacteria developing resistance to the drugs, which could drive us towards a future where once-simple infections become life-threatening again. Now, researchers at Purdue University have found that blue light can weaken a particularly nasty "superbug" and make it vulnerable to even mild antiseptics again.

Staphylococcus aureus is a common bacteria that's mostly pretty harmless, but certain strains can cause more problems. Methicillin-resistant Staphylococcus aureus (MRSA) is a particularly troublesome bug that's most dangerous to people whose immune systems are already compromised, meaning it can wreak havoc in hospitals and retirement homes. Unfortunately it's getting harder and harder to treat – it's not just resistant to methicillin as its name suggests, but also an ever-growing list of other common antibiotics.

New antibiotics are in the works, but of course eventually bacteria will inevitably develop resistances to those too. So scientists are trying to find longer-term solutions that superbugs won't be able to adapt to, such as material surfaces that tear them apart or nanoparticles that produce toxic molecules when triggered by light.

Mohamed Seleem, an author of the study
Mohamed Seleem, an author of the study

In a similar vein, the Purdue researchers have developed their own form of light therapy. The team found that MRSA can be weakened through "photobleaching" – essentially sapping the color of the bacteria by exposing it to blue light. Since these pigments are part of how the bugs can infect a host, this can reduce their ability to cause harm.

"When you bleach something in the wash machine, you're extracting the color using chemicals," says Mohamed Seleem, an author of the study. "What we're doing here is similar, but we're using blue light."

The light itself isn't killing the MRSA – instead, it lowers its defenses enough for drugs and other molecules to finish it off, even those that the bugs would normally be resistant to. In tests on mice with MRSA-infected wounds, the researchers found that mild antiseptics like hydrogen peroxide were effective at destroying bacteria weakened by blue light.

The team has patented a device that uses this technology to treat MRSA-infected wounds. The idea is that it would take the form of a small box with a light in it, which shines through a hole onto the wound. Importantly, the light has been found to be safe on mammalian cells.

"This new tool can treat any superficial wound infected with MRSA, which are typically very difficult to treat," says Seleem. "The device itself is very small and easy to use. We're hoping that in the next few years, anyone could carry it around in their purse."

The research was published in the journal Advanced Science.

Source: Purdue University

I think I did this about 12 years ago. I was kept in a hospital for observation for 10 hours with an open wound on the back of my head. About a month later I developed a hand wound that would not heal. I went back to the hospital and they wrapped it up and gave me 2 different antibiotics. I went home, took the pills and had to go back for more due to nothing being killed and it started spreading over and around my right hand. After taking the 2nd dose of pills for a week or so, I became panicky and started doing an internet search for something that might work. I discovered Russian research on light therapy, went into my kitchen and pulled an old style LED flashlight from a drawer and started shining it on my hand that was looking like frog eggs were growing under the skin. I stopped after 45 minutes. When I looked at my hand the next morning all of the infection had turned brown, dead. I tossed the remaining pills and started telling people about it. They all looked at me like I just swallowed some psychedelic mushrooms.
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Can this actually be patented? A combination of blue plus related UV light has been used for more than 10 years for killing bacteria colonies growing in cooling tower and other building water systems. The weakness of course is that most bacteria may "hide" behind suspended particles, which may be the reason they survive there, so that good particle filtration and multiple recirculation is needed to approach total elimination. This kind of "engineering" difficulty, i.e. the practicalities applies just as much to the medical world as to anywhere else.
To be complete, this article should have mentioned that it was not "blue light" generally that had this effect, but a specific wavelength which happens to lie in the area perceived as being blue. The absorption of staphyloxanthin in bacterial cells occurs at 460nm, and that is the light that was used, likely monochromatic and produced by a laser or LED..